SE1950193A1

SE1950193A1 - Manufacture of a titanium compound structure and a structure

Info

Publication number: SE1950193A1
Application number: SE1950193A
Authority: SE
Inventors: Anders Teigland; Andre Marcel Bienfait; Andreas Westermoen; Hjørdis Skår; Robert William Corkery
Original assignee: Joma Int A/S
Priority date: 2019-02-15
Filing date: 2019-02-15
Publication date: 2020-08-16
Also published as: SE543124C2

Abstract

The present invention relates to a method for manufacturing a structure of a titanium compound selected from the group consisting of sheets, wires and tubes. The present invention also relates to intermediate products and structures comprising titanium dioxide obtainable by the method.

Description

lO MÄNUFÄCTURE OF TITANIUM DIOXIDE STRJCTURES Technical Field The invention relates to a method for forming structures of a titanium comoouid, the structures consisting of tubes, sheets, and/or wires. The invention further relates to an intermediate dispersion comprising titanium dioxide particles and an intermediate sol comprising titanium dioxide particles as well as to a structure comprising titanium dioxide in the form of tubes, sheets or wires. long nanostructures, such as nanotubes, nanowires, and nanofibers have been studied for applications such as pollutants absorption and cata_7fis, photooatalysis, i-“l.| Na :nd { ,.:,..4,..4 ,i~ on batteries, is, sensors, sensing techniques. Titanium dioxide high surface area and high ion axcnange capabilities which makes them more suitable far cation substitution in various applications. TiO2(B), a titanium dioxide polymorph, herein also referred to as “hronze' is for lithium ion hatteries due oroperties, not limited to its capacity, dimensivnal environmental profiie and non~flammability. Among the said favourable properties, these lend it favourableuser properties in applications where ”ast o cycling stahility, and high current demann are desirable. titanium dioxide structures such as tubes and sheets are typically starting with titanium 1 dioxide particles or powders, which are dispersed in a liquid.

WO 2015/038076 discloses a method of forming titaniumdioxide nanotubes, the method comprising: heating aclosed vessel containing a titanium dioxide precursor powder dispersed in a base, wherein content in the closedvessel is simultaneously stirred with a magnetic stirrerduring the heating. Battery anodes and their manufacture are also disclosed.

CN 103693681 discloses a method for preparing ultra-long titanic acid micro-nanotubes using titaniumdioxide powders by a low-temperature stirringhydrothermal method, which comprises using titaniumdioxide and sodium hydroxide as raw materials in powder form to carry out hydrothermal reaction.

KR 20080057102 discloses a method of manufacturing atitanium dioxide nanotube starting with a sol comprisingthe steps of adding a titanium dioxide sol to astrongly alkaline aqueous solution, heating thestrongly alkaline aqueous solution, addinghydrochloric acid to the strongly alkaline aqueoussolution to adjust pH and washing with water. Atitanium dioxide particle sol is mentioned to have aparticle size of 30 nm or less. In the examplesparticles sizes of 20-30 nm is mentioned without addedmetal ions. Addition of different ions such as vanadium ions reduce the particle size to about 5 nm. lO The most common methods in the prior art start with dispersing particles (powder) in a concentrated NaOH solution to obtain a suspension. This creates a number of problems. of the art includ: püwdïrÄmentation that results in aninhomogeneous distribution of reactants, ihhibition oflow reaction inhioitinn o .h surfaces, diffusion and mass transport within and hear thepowder aqgregates, inhomogeneous reaction rates the dimented powder seagqregates and exacerbation of these problems at = w increasing loaßs of particles. When the particies are dispersed in a liquidstep to separate suspension, which may be time and energy consuminq.

Even then, if the source was a powder comprised of anaqqlomeration of large particles, stirring wii notmake these large particles smällar.

A further problem may occur if the method starts witha sol comprised of dispersed small particles, since these particles may Ei .lf ä lt is desired to have a high specific surface area of dispersed particles used to manufacture the structure(i.e. tubes, wires and sheits) and to provide an lO l å and economical process fo- efficientstructures in titanium dioxide,Summary It is an object of the present invention to alleviate at least some of the problems in the prior art and toprovide a method for manufacturing structures ofsuch wires and/or titanium compounds, as sheets, tubes, which exhibit improved synthesis, enhanced properties of the resulting structures, and improved range of use.

The titanium compound may be an alkali metal titanate,a protonated titanate or titanium dioxide (TiOﬁ.A sheet manufactured by a method according to the present disclosure may be curved.

The titanium structures manufactured by a methodaccording to the present disclosure have manyapplications such as in osteointegration, catalysis, photo catalysis, water treatment, manufacture of electrodes for batteries, including anodes for lithium and sodium ion batteries.

In a first aspect there is provided a method formanufacturing a structure of a titanium compoundselected from the group consisting of sheets, wiresand tubes, the method comprising the steps of a)providing at least one titanic acid with the generalformula [TiOX(OH)44X]n and dissolving it in an aqueoussolution comprising at least one selected from theand HCl so that a group consisting of TiOCl2, TiClh clear solution is obtained, wherein the pH of theclear solution is lower than 1 after dissolution;b)increasing the temperature of the clear solutionuntil reaching a temperature in the interval 68-85 °Cwhere precipitation starts to occur, adding at leastone acidic stabilizer before the precipitation startsto occur, and holding that temperature during at least1 minute during stirring to obtain a dispersion ofparticles comprising TiO2 as an intermediate product;c) adjusting the concentration of hydroxide ions inthe dispersion from step b) to at least 8 M by addingan alkali metal hydroxide MOH; d) treating thedispersion from step c) at a temperature in theinterval 90-170 °C during 6-72 hours to obtain aplurality of first structures comprising alkali metaltitanate; e) treating the plurality of firststructures comprising alkali metal titanate toexchange at least a part of the alkali metal ions M*with H* to obtain a plurality of second structures comprising protonated titanate.

A clear solution as obtained above is defined as beingnearly or completely transparent to visible light withlittle or no detectable cloudiness or scattering ofvisible light by undissolved titanic acid and may bedetermined by shining a visible light laser throughthe solution until it passes straight through thesolution with little to no detectable scattering ofvisible light from within the solution to the nakedeye. Alternately it may be detected in practise whenordinary 12 point printed text is resolved through a 10cm path-length of the solution held in a glass pipe. lO MOH denotes an alkali metal hydroxide, wherein “M” denotes the alkali metal. The alkali metal hydroxide(MOH) may be selected from the group consisting of sodium hydroxide (NaOH) and potassium hydroxide (KOH).One advantage of this method is that the particle sizein a sol made this way can be tuned by adjusting theratio of dissolved titanic acid to the amount ofTiOCl2 solution used to dissolve the titanic acid.

In one embodiment, the method further comprises, after step b) and before step c), the steps of bl)decreasing the content of ions in the dispersionpreferably such that the ion concentration is loweredto a point where a sol is formed, wherein the averagediameter of the particles in the sol is 3-20 nm, 4.5-7 nm, and b2) preferably 4-l5 nm, more preferably, adjusting the concentration of TiO2 in the dispersionof 10-80%,20-70%, -50%. preferably to a value within the range more preferably to a value within the range mostpreferably to a value within the rangeThis results in and b2), a sol being formed after steps bl)which may then used to produce the structures comprising a titanium compound.

Step bl) may be performed before step b2). Steps bl)and b2) may be repeated several times.Step b2) may be performed before step bl). Steps b2)and bl) may be repeated several times. l0 An advantage of a method comprising steps bl) and b2) is increasing the TiO2 concentration without concentrating other species in the dispersion.

After steps bl) and b2) an alkali sol of TiO2 is formed.

In a second embodiment, the dispersion after step b) or the sol after steps bl) and b2) comprises at least l5 wt% titanium dioxide, preferably at least l7 wt% titanium dioxide, more preferably at least 25 wt% titanium dioxide, even more preferably at least 30 wt% titanium dioxide, and even more preferably at least 40 wt% titanium dioxide, and most preferably at least 50 wt% titanium dioxide.

Preferably, the dispersion after step b) or the solafter steps bl) and b2) comprises 80 wt% titaniumdioxide or less. Thus, the dispersion after step b) or the sol after steps bl) and b2) may comprise l5-80 wt%, l7-80 wt%, 25-80 wt%, 30-80 wt%, 40-80 wt%, or50-80 wt% titanium dioxide.

A high content of titanium dioxide (TiO2) is desired because it leads to higher density dispersionsrelative to those of lower concentrations. Higherdensity dispersions means more titanium dioxide in a given volume, which can translate directly to higher yields for a fixed volume reactor. Additionally, it isdesired as it reduces the overall volume ofdispersions used per unit of titanium dioxide, which can be an advantage in lowering costs and time related to storage and handling. l0 In another embodiment, the plurality of secondstructures comprising protonated titanate obtained are heated to a temperature in the range600 °C, 400 after step e)300 - 700 °C,300 - 450 °C, preferably 300 - more preferably most preferably 300 - °C to obtain aplurality of third structures comprising titaniumdioxide.

Thus, the method according to the present disclosure may further comprise, after step e), the step of f)heating the plurality of second structures comprisingprotonated titanate obtained after step e) to a700 °C, 450 °C, temperature in the range 300 - preferably 300 - 600 °C, more preferably 300 - most preferably 300 - 400 °C to obtain a plurality of third structures comprising titanium dioxide.

In a further embodiment, the at least one acidicstabilizer is selected from a carboxylic acid, and analpha hydroxy acid.

In yet another embodiment, at least one alkanolamine and at least one acidic stabilizer are added together before step c).

One advantage of adding at least one alkanolamine andat least one acidic stabilizer together before step d)is that it stabilizes particles against aggregation atpH values above the isoelectric point of titanium dioxide. lO In a further embodiment, the carboxylic acid is selected from the group consisting of citric acid, and lactic acid. In another embodiment, the carboxylicacid is selected from the group consisting of citrictartaric acid, and lactic acid." acid, malic acid, Such alpha hydroxy acids are particularly preferred because they have first pKa's S 3.8, can complex withTi, can limit particle growth and can stabilizeparticles against aggregation over a range of pHvalues.

In another embodiment, stirring is performed duringstep d).

Stirring during step d) homogenises the reactionmedium leading to homogeneous reaction conditions andpreferentially enhances crystal growth in onedimension so that longer tubes are formed.

According to yet another embodiment, the dispersionhas remained in a dispersed state without drying andsubsequent redispersion between steps b) and c).This has the effect that no powders need be handledand c). between steps b) In a further embodiment, the dispersion is dried and redispersed between steps b) and c).This has the effect that the titanium dioxide ismaximally concentrated for a given dispersion and so can be stored and, processed and handled in smaller volumes compared with dispersions of the same titaniumcontent.

In yet another embodiment, the specific surface area,as measured according to ISO 9277 of the particlesdried from the dispersion obtained after step b), is in the range 200-300 m?/g.

A specific surface area in the range 200-300 m?/g hasthe effect of indicating the particles in thedispersion also have a high specific surface areaavailable for reaction in step d) therefore a highrate of reaction in step d).

In a further embodiment, the pH after dissolution instep a) is lower than 0.In a further embodiment, the pH of the dispersionresulting from step b)bl) and b2) 1.5. or the sol resulting from steps is adjusted to a value in the range 0.5- This has the effect of obtaining an acidic sol.In another embodiment, the concentration of hydroxideions is adjusted in step c) using NaOH.

One advantage of adjusting the pH using NaOH is thatit that NaOH is inexpensive compared to KOH.According to yet another embodiment, the titanic acidprovided in step a) is made from a TiOCl2 by neutralisation until precipitation by an aqueous solution of NaOH. lO ll According to a further embodiment, the plurality offirst structures comprising alkali metal titanate areseparated from the remaining liquid between steps d)and e).

This is advantageous, since this lowers the NaOHcontent before step e).

According to yet another embodiment, the treatment ofthe dispersion in step d) is performed at autogenous pressure.

This has the effect that the pressure need not beregulated to a certain value nor monitored.According to a further embodiment, no transition metal ions except titanium are added.

The present disclosure also provides a method for manufacturing a dispersion of particles comprisingTiO2 and comprising at least one acidic stabilizer,and b). the method comprising the steps a) All modifications of the steps a) and b disclosed hereinalso apply to this method for manufacturing adispersion of particles comprising TiO2 and comprising at least one acidic stabilizer.

The present disclosure also provides a method formanufacturing a sol of particles comprising TiO2 andcomprising at least one acidic stabilizer, the methodb), bl) and b2). b), bl) and b2) comprising the steps a), All modifications of the steps a), 12 disclosed herein also apply to the method formanufacturing a sol of particles comprising TiO2 and comprising at least one acidic stabilizer.

The present disclosure also provides a method formanufacturing a structure comprising alkali metalb), C) titanate, the method comprising the steps a), and d). One embodiment of this method also comprisesthe steps bl) and b2). All modifications of the stepsa), b), bl), b2), c) and d) disclosed herein also apply to the method for manufacturing a structure comprising alkali metal titanate.

The present disclosure also provides a method formanufacturing a structure comprising protonatedb), c), titanate, the method comprising the steps a), d) and e). One embodiment of this method alsocomprises the steps bl) and b2). All modifications ofthe steps a), b), b1), b2), c), d) and e) disclosed herein also apply to the method for manufacturing a structure comprising protonated titanate.

The present disclosure also provides a method for manufacturing a structure comprising titanium dioxide,the method comprising the steps a), b), c), d), e) andf). One embodiment of this method also comprises theand b2). b2), C), d), e) steps bl)b), bl), All modifications of the steps a),and f) disclosed herein alsoapply to the method for manufacturing a structure comprising titanium dioxide.

According to a second aspect of the invention, an intermediate product obtained after step b) of the 13 method is provided, the intermediate product being adispersion of particles comprising TiO2 and comprisingat least one acidic stabilizer.

The dispersion may comprise at least 15 wt% TiOh preferably at least 17 wt% TiO2, more preferably at least 25 wt% TiO2, even more preferably at least 30wt% TiO2, even more preferably at least 40 wt% TiOh and most preferably at least 50 wt% titanium dioxide.

Preferably, the dispersion comprises 80 wt% titanium dioxide or less. Thus, the dispersion may comprise 15- 80 wt%, 17-80 wt%, 25-80 wt%, 30-80 wt%, 40-80 wt%, or50-80 wt% titanium dioxide.

A high content of titanium dioxide (TiO2) is desiredbecause more titanium dioxide is contained in a givenvolume which can provide an economic advantage instorage, processing and handling of higherconcentrated dispersions relative to lowerconcentration dispersions.

Furthermore, the at least one acidic stabilizer may beat least one selected from a carboxylic acid, and analpha hydroxy acid.

Preferably, the carboxylic acid is selected from the group consisting of citric acid, and lactic acid. Suchalpha hydroxy acids are particularly preferred becausethey have first pKa's S 3.8, can complex with Ti, canlimit particle growth and can stabilize particles against aggregation over a range of pH values. 14 Moreover, the pH may be in the range 0.

The pH may be 0.5- 1.5. adjusted to a value in the range This has the effect of yielding an acidic sol.

The pH may be 5.5- 7.5. adjusted to a value in the range This has the effect of yielding a neutral sol.

The pH may be adjusted to a value in the range 7.5-9.This has the effect of yielding an alkaline sol.Furthermore, the specific surface area measuredaccording to ISO 9277 of the particles dried from thedispersion may be in the range 200-300 m2/g.

A specific surface area in the range 200-300 m?/g hasthe effect of indicating that the particles in thedispersion also have a high specific surface areaavailable for reaction in step d) therefore a highrate of reaction in step d).

Thus, an intermediate product is provided, wherein theintermediate product is a dispersion of particlescomprising TiO2 and comprising at least one acidicstabilizer and wherein the intermediate productoptionally exhibits one or more of the followingfeatures: - the dispersion comprises at least 15 wt% TiO@ preferably at least 17 wt% TiO2, more preferably at least 25 wt% TiO2, even more preferably atleast 30 wt% TiO2, even more preferably at least 40 wt% TiO2, and most preferably at least 50 wt% titanium dioxide; - the at least one acidic stabilizer is at least one selected from a carboxylic acid, and analpha hydroxy acid; - the pH is in the range 0.5 - 9; - the specific surface area measured according to ISO 9277 of the particles dried from the dispersion is in the range 200-300 m?/g.

According to a third aspect, and b2) an intermediate product obtained after steps bl) of the method is provided, the intermediate product being a sol of particles comprising TiO2 and comprising at least one acidic stabilizer.

The sol may comprise at least 15 wt% TiO2, preferably at least 17 wt% TiO2, more preferably at least 25 wt% TiO2, even more preferably at least 30 wt% TiO2, even more preferably at least 40 wt% TiO2, and most preferably at least 50 wt% titanium dioxide.

Preferably, the sol comprises 80 wt% (percentage by titanium dioxide or less. Thus, 17-80 Wt%, 25-80 Wt%, weight) the sol may comprise 15-80 wt%, 30-80 wt%, 40-80 wt%, or 50-80 wt% titanium dioxide.

A high content of titanium dioxide (TiO2) is desiredbecause more titanium dioxide is contained in a givenvolume which can provide an economic advantage in storage, processing and handling of higherconcentrated dispersions relative to lower concentration dispersions. 16 Furthermore, the at least one acidic stabilizer is at least one selected from a carboxylic acid, and analpha hydroxy acid.

Preferably, the carboxylic acid is selected from thegroup consisting of citric acid, and lactic acid.

Moreover, the pH may be in the range 0.5 - 9.

The pH may be 5.5- 7.5. adjusted to a value in the range This has the effect of yielding a neutral sol.The pH may be adjusted to a value in the range 7.5-9.This has the effect of yielding an alkaline sol.Furthermore, the specific surface area measuredaccording to ISO 9277 of the particles dried from the dispersion may be in the range 200-300 m2/g.

Thus, an intermediate product is provided, wherein theintermediate product is a sol of particles comprisingTiO2 and comprising at least one acidic stabilizer andwherein the intermediate product optionally exhibits one or more of the following features: 17 - the sol comprises at least 15 wt% TiOb preferably at least 17 wt% TiO2, more preferably at least 25 wt% TiO2, even more preferably atleast 30 wt% TiO2, even more preferably at least 40 wt% TiO2, and most preferably at least 50 wt% titanium dioxide; - the at least one acidic stabilizer is at leastone selected from a carboxylic acid, and an alpha hydroxy acid;- the pH is in the range 0.5 - 9; - the specific surface area measured according toISO 9277 of the particles dried from the sol isin the range 200-300 m?/g.

The present disclosure also provides an intermediate product obtained after step d) of the method disclosedherein, the intermediate product being a structurecomprising an alkali metal titanate. The structurecomprising an alkali metal titanate is thus obtainedby a method comprising the steps a), b), c) and d), and optionally comprising the steps b1) and b2), as disclosed above. Preferably, the structure comprising an alkali metal titanate is in the form of a sheet, a wire and/or a tube.

The present disclosure also provides an intermediate product obtained after step e) of the method disclosed herein, the intermediate product being a structure comprising a protonated titanate. The structure comprising a protonated titanate is thus obtained by a method comprising the steps a), b), c), d) and e), and optionally comprising the steps b1) and b2), as disclosed above. Preferably, the structure comprising 18 a protonated titanate is in the form of a sheet, a wire and/or a tube.

The present disclosure also provides an intermediateproduct obtained after step f) of the method disclosedherein, the intermediate product being a structurecomprising titanium dioxide. The structure comprisingtitanium dioxide is thus obtained by a methodcomprising the steps a), b), c), d), e) and f), and b2), as andoptionally comprising the steps b1)disclosed above.

Preferably, the structure comprising titanium dioxide is in the form of a sheet, a wireand/or a tube.

According to a fourth aspect, a structure comprisingtitanium dioxide is provided, said structure being one of a sheet, a wire, and a tube, said structure being made according to the method disclosed herein.The structure may constitute a part of a Li ion or sodium ion battery anode.

The structure may constitute a part of a photocatalytic object.

The structure may constitute a surface modification or treatment of a titanium dental or bone implant.

The present invention also discloses the use of a highly concentrated sol comprising titanium dioxidewires and tubes. The sol b), bl and b2) as particles for making sheets,may be obtained by the steps a), described herein. The sol comprises at least 15 wt% 19 titanium dioxide, preferably at least 17 wt% titaniumdioxide, more preferably at least 25 wt% titaniumdioxide, even more preferably at least 30 wt% titaniumdioxide, and even more preferably at least 40 wt% titanium dioxide, and most preferably at least 50 wt% titanium dioxide. Preferably, the sol comprises 80 wt% titanium dioxide or less. Thus, the dispersion afteror the sol after steps bl) and b2) 17-80 wt%, 25-80 wt%, step b) may comprise 15-80 wt%, 30-80 wt%, 40-80 wt%, or 50-80 wt% titanium dioxide.Advantages of the invention include the possibility ofhaving smaller diameter structures and or comprising thinner walls of the sheets, wires or tubes, thelatter giving larger specific surface areas for the obtained structures as well as a lower probability ofagglomeration during reaction and thus faster kinetics in forming the said structures.

Brief description of the Figures Fig 1 shows X-ray powder diffraction (XRD) patternscorresponding to the product of heat treating theplurality of second structures obtained from experiment RWC-1-018 of Tables 1 and 2.

Fig 2 shows Raman spectra of the same samples inFigure 1.Fig 3 shows X-ray powder diffraction (XRD) patterns corresponding to the product of heat treating theplurality of second structures obtained from experiment RWC-1-019 of Tables 1 and 2.

Fig 4 shows Raman spectra of the same samples inFigure 3.Fig 5 shows X-ray powder diffraction (XRD) patterns corresponding to the product of heat treating theplurality of second structures obtained from experiment RWC-1-022 of Tables 1 and 2.

Fig 6 shows Raman spectra of the same samples inFigure 5.Fig 7 shows X-ray powder diffraction (XRD) patterns corresponding to the product of heat treating theplurality of second structures obtained from experiment RWC-1-024 of Tables 1 and 2.

Fig 8 shows Raman spectra of the same samples inFigure 5.

Fig 9 shows the Ti/Na ratio measured from EDX (seeTable 2) versus the specific surface area of the 350 °C treated samples, as discussed in the caption to Figure 1.

Fig 10 shows an SEM image of sample RWC-1-005, withwell formed elongate aggregated clusters of tubes/rodsforming a porous solid.

Fig 11 shows a TEM image of sample RWC-1-005, withwell formed tubes forming an open structured web ornetwork of varying degrees of compactness likely induced by the TEM sample preparation. 21 Fig 12 shows a TEM image of sample RWC-1-O17, withwell formed long tubes forming an aggregate ofparallel tubes, surrounded by shorter pieces of tubes,many likely broken during the grinding and sonicationused in sample preparation.

Fig 13 shows an SEM image of sample RWC-1-018, with well-formed elongate, curved and twisted tubes/rodsforming an aggregated porous solid.with Fig 14 shows an SEM image of sample RWC-1-020, well-formed elongate, curved and twisted tubes/rodsforming an aggregated porous solid.Fig 15 shows an SEM image of sample RWC-1-024, with well-formed elongate, curved and twisted tubes/ribbonsforming an aggregated porous solid.Fig 16 shows a zoomed in view of the SEM image ofsample RWC-1-024 seen in Figure 14, clearly showingthe diameter of individual tubes/ribbons asapproximately 3-8 nm.

Fig 17 shows the adsorption (squares) and desorption (diamonds) branches of the nitrogen physisorption isotherm at 77 K corresponding to JAT-1-017 of Tables1 and 2.Fig 18 shows the BJH desorption pore size distribution derived from the desoption branch of Figure 17. 22 Fig 19 shows crystal structures comprising TiO6 octahedra described herein, namely the first, second and third structures)(1-3), and a single layer of thesecond structure rolled into a tube (4-6).Table 1 Table 2 shows conditions for the examples. shows results from the examples.

Detailed description The following detailed description discloses by way ofexamples details and embodiments by which the invention may be practised.

It is to be understood that the terminology employedherein is used for the purpose of describingparticular embodiments only and is not intended to belimiting since the scope of the present invention islimited only by the appended claims and equivalentsthereof.

If nothing else is defined, any terms and scientificterminology used herein are intended to have themeanings commonly understood by those of skill in theart to which this invention pertains.

It should be noted that, as used in this specification \\ \\ a”, an l/ and the attached claims, the singular termsand “the” may in some cases be construed to includeplural terms, unless the context clearly dictatesotherwise.

A *clear solution' is defined as being nearly or completely transparent to visible light with little or lO 23 no detectable cloudiness or scattering of visiblelight by undissolved titanic acid and may bedetermined by shining a visible light laser throughthe solution until it passes straight through thesolution with little to no detectable scattering ofvisible light from within the solution to the nakedeye. Alternately it may be detected in practise whenordinary 12 point printed text is resolved through alOcm path-length of the solution held in a glass pipe.“Stabilizer' as used throughout the description andclaims denotes a substance which interacts with thetitanium dioxide particles and which is utilized tocontrol factors such as agglomeration and dispersionof the titanium dioxide particles. Stabilizer issometimes referred to as a capping agent and furtherhas the effect that the titanium dioxide particles donot become so large during the manufacture. Withoutwishing to be bound by any specific scientific theorythe inventors believe that the stabilizer binds to thetitanium dioxide particles, and thereby affects thesurface properties and colloidal behaviour of thetitanium dioxide particles, in particular with respectto their agglomeration, and so enhancing the colloidalstability of individual nanoparticles in a sol.Further, for crystalline matter in the titaniumdioxide particles the stabilizer may bind differentlyto different crystal planes and thereby modify thecrystallization habit.

“XRD' “SEl/l' denotes X-ray powder diffraction, denotes scanning electron microscopy, *TEM' denotes transmission electron microscopy, *EDX' denotes energy lO 24 dispersive x-ray analysis, *TGA' denotes thermogravimetric analysis, and SEI denotes solid-electrolyte interphase.*Specific surface area', sometimes referred to as BETsurface area or BET area, is the surface area measuredin units of m?.g* determined according to ISO 9277.“Dispersion' as used throughout the description andclaims can be a suspension or a sol.

“Suspension' as used throughout the description andclaims are solid particles in a liquid medium. For a suspension the particles are at least partially so large that they settle after some time due to gravity.

*Sol' as used throughout the description and claims isa type of colloid in which the dispersed phase is solidand the dispersion media is liquid. In general, a sol isessentially stable and the particles do not settle bygravity. Although a sol is in general stable, there maybe exceptional solid particles, which settle anyway. Evenif a sol is described as stable a skilled person realizesthat there may be some very few larger particles whichmay settle anyway. Such larger particles can be regarded as an impurity.

For some dispersed solid particles in a liquid it may bethe case that some of the particles are so small that they do not settle, whereas other particles are largerand settle due to gravity over time. For such mixtures the term sol can also be used.

*Wt%' denotes percentage by weight.

*Titanium oxide' as used throughout the descriptionand claims denotes all possible oxides of titanium,including but not limited to titanium(II)oxide TiO,titanium(III)oxide Ti2O3, titanium(IV) oxide TiO2. Theterm titanium oxide further includes but is notlimited to Ti3O, Ti2O, Ti3O5, and Ti4O7. A skilledperson realizes that titanium oxides may form varioushydrates also known as amorphous titania whereby aVariable fraction of TiOH groups exist with Ti oxidesand these can convert to Ti oxide via water release.All such hydrates are encompassed within the term. Ofparticular interest is titanium dioxide TiO2.

The relative acidity (A) is defined in terms of the mass ratio, “M', where M is the ratio of the mass Ti in a neutralised suspension titanic acid at pH 5.5 andto the mass of Ti in the aqueous solution used in stepthe relative a) to dissolve the titanic acid. Herein, acidity is defined to be A=1/M. In Example 1 below, the ratio, M of two masses was 3:7, or expressed as afraction, the ratio can be expressed, R=3/7 = 0.43, Inthis case A=l/0.43 = 7/3 = 2.333. R=1:9 to 9:1, orR=1/9 to 9, or A = 0.11 to 9 were explored and particle sizes and yields were examined after step b).Towards higher A values mean particle size was smallerand yields were lower. Towards lower relative acidityvalues, A, particle sizes were larger and yields werehigher. For those skilled in the art it is understoodthat nucleation occurs at the first stage of particleformation, and it is believed that this occurs justprior to precipitation of the intermediate productit is during step b). At this nucleation stage, believed that a higher relative acidity A, will favour lO 26 a larger total number of nuclei and lower yields afterstep b) due to the relatively higher solubility of the dissolved Ti species at high relative acidity. At this nucleation stage, it is believed that a lower relative acidity A, will favour a smaller total number of nuclei and higher yields after step b) due to the relative lower solubility of the dissolved Ti species at high relative acidity. Those skilled in the art realize that the particle sizes and yields indicatedby the relative acidity, A will also depend ondifferences in compositions of the starting materials,for example the acid content. However for practicalpurposes, it is preferred for ease of processing,costs and quality control to use the same source batchfor all the Ti containing species of step a), makingthe ratio A easy to calculate from solution massesalone for a given composition. as used throughout the *Structure' or *structures' description and claims denotes any structures(including their hydrates), typically built up ofcompounds comprising layered alkali metal titanates,layered protonated titanates and titanium dioxides TiO2(B) - *bronze' or TiO2 - anatase, the latter TiO2structures also includes bronze and anatase structureswires and tubes with various crystal defects. Sheets, are encompassed within the term. The tubes, wires andsheets are sometimes referred to as nanotubes, nanowires and nanosheets because of their size. A tubeis generally considered to be hollow inside. A wire isgenerally considered not to be hollow inside. Since itsometimes may be experimentally difficult to distinguish between hollow tubes and non-hollow wires lO 27 the terms are sometimes used interchangeably so thattube sometimes may denote non-hollow tubes, i.e.wires. A sheet is a structure having three dimensions,or two dimensions if its thickness is very small (atleast one to two orders of magnitude) compared to thelength and width dimensions of the sheet.

The titanates formed at steps d) and e), are believedto be of a layered structure with general formulaA2Ti¿bnﬂ where A is one of hydrogen or an alkalin is 3 to 6. metal, These can also form hydrates such as H2Ti4b.H2O and H2Ti¿h¿.2.5H2O. The layers may bedefined as the corrugated or stepped layers of TiO6polyhedra that make up the monoclinic unit cell of thetitanate layer structures. Other layered titanateforms are known which have non-corrugated, non-steppedlayers and have an othorhombic unit cell. The layersare charged and interlayer Na or H ions counterbalancethe charges of the layers. A *stack of layers' ishereby defined as a sheet of one or more layers.“Delamination' is defined as when one or more layersseparate from a sheet comprising one or more layers.Delamination increases the likelihood of formingcurved structures. Single layers are thin andrelatively flexible and can bend, roll, fold orotherwise deform into a plethora of curved shapes,with radii of curvature (r) more likely to be smallerthe thinner the layer stack for a given bending stress.

The types of curved structures formed from full or partially delaminated layers include, but are not lO 28 limited to, those structures which curve primarily along one direction only - these can be open or closed seam tubes, scrolls, half pipes, cones, ribbons andother layer structures that have zero Gaussiancurvature (K) and some finite mean curvature (M) (notincluding the points at the edges of the sheets).Gaussian curvature is the product of the two principlecurvatures at a point on the surface, k1=l/rl andk2=l/rg at a point on the sheet and mean curvature isthe average of the two principle radii of curvature at a point on the sheet.

More complex curved structures can form if the sheetsbend in in two directions so that the Gaussiancurvature is non zero (positive or negative) if thelayers are sufficiently distorted for example throughbond rearrangements, bond breakage and localcompositional variations.

Further, more complex structures can form when aplethora of individual structures comprising one ormore of the said curved structures assemble into superstructures including but not limited to mesoporousbundles and and/or macroporous networks, sponges, films. In the latter case of films, the networkstructure can be formed from previously undriedof structures blade suspensions, i.e. a dispersion or a sol, by a variety of methods including casting, coating, spin coating, spraying, dipping, or by subjecting previously constructed films of TiO2nanoparticles to one or more of the steps c-f disclosed herein for manufacturing a structure of a l0 29 titanium compound selected from the group consisting of sheets, a wires and tubes. )), through several intermediate stages Upon heating (step layered titanate structuresare believed to goof condensation of adjacent layers and dehydration,and can eventually form TiO2(B) 300 °C. above approximatelyIt is believed that the same progression fromlayered titanate to TiO2(B) can occur for the curvedstructures, albeit with some expecteddistortions/defects in the crystal structures relativeto those that are substantially uncurved. In caseswhere high alkali metal/Ti ratio exists in theprecursor layer structure, the product of heating mayalso include the alkali metal bronze structure MXTiO@which has the same Ti-O network structure as TiO2(B).At temperatures lower than that required to formTiO2(B), an intermediate product can also form duringheating of proton rich titanates that has a structureclose to TiO2(B). Such structural progression duringheating has been considered by Feist et al., Journal of Solid State Chemistry l0l, 275-295 (1992). Theypointed out that different hydrate step lengths ofprotonated hydrates can result in differing Raman spectra, indicating differing degrees of crystallineorder for the TiO2(B) formed from them and so we heredefine TiO2(B)as also including these variants and theTiO2(B) (l992), like intermediate considered by Feist et al.since they are sometimes difficult todistinguish and quite possibly coexist in the heated structures disclosed herein.

According to the present disclosure, a method formanufacturing a structure of a titanium compound selectedfrom the group consisting of sheets, wires and tubes is provided. The method comprises the steps of a) providing at least one titanic acid withthe general formula [TiOX(OH)44X]n and dissolving it inan aqueous solution comprising at least one selectedand HCl so from the group consisting of TiOCl2, TiClh that a clear solution is obtained, wherein the pH of the clear solution is lower than 1 after dissolution;b)increasing the temperature of the clear solution 68-85 until reaching a temperature in the interval°C where precipitation starts to occur, addingat least one acidic stabilizer is before theprecipitation starts to occur, and holding thattemperature during at least 1 minute during stirringto obtain a dispersion of particles comprising TiO2 asan intermediate product; c) adjusting the concentration of hydroxideions in the dispersion from step b) to at least 8 M byadding an alkali metal hydroxide MOH; d) treating the dispersion from step c) at atemperature in the interval 90-170 °C during 6-72hours to obtain a plurality of first structurescomprising alkali metal titanate; and e) treating the plurality of first structurescomprising alkali metal titanate to exchange at leasta part of the alkali metal ions M* with H* to obtain aplurality of second structures comprising protonated titanate. lO 3l The method may further comprise, after step b) and before step c), the steps ofbl) decreasing the content of ions in the dispersion preferably such that the ion concentrationis lowered to a point where a sol is formed, whereinthe average diameter of the particles in the sol is 3-20 nm, preferably 4-l5 nm, more preferably, 4.5-7 nm,and b2) adjusting the concentration of TiO2 in thedispersion preferably to a value within the range oflO-80%,20-70%, -50%. more preferably to a value within the range most preferably to a value within the range This results in a sol being formed after steps bl) and b2), which may then used to produce the structuresStep bl) and b2) comprising a titanium compound. may be performed before step b2). Steps bl) may beStep b2) and bl) repeated several times. may be performed before step bl). Steps b2) may be repeated several times.The titanic acid provided in step a) may be made byneutralizing a TiOCl2 solution by addition of an aqueous solution of NaOH so that the titanic acid precipitates and flocculates as a white solid phase.

In one embodiment, the pH after dissolution in step a) is lower than O.

It is difficult to measure low pH values such as lowerthan O, and instead an estimate can be made based oncalculated H* concentration. The calculated pH for the clear solution obtained after step a) and b) of lO 32 example l below was approximately -0.8. This valuecould be lower or higher depending upon the acidcontent of the TiOCl2 solution added to dissolve theprovided titanic acid of step a) and the amount ofthat TiOCl2 solution added to dissolve the titanicacid of step a). In Example l it is also clear thatthe pH after step a) is also dependent upon the pH ofthe aqueous suspension of titanic acid formed by neutralisation with NaOH. In this respect the pH afterdissolution of step a), even if not known precisely,can be understood by a relative acidity calculation(as described above) for a given Ti source or sourcesof all titanium compounds in step a), i.e., where theprovided, at least one titanic acid is dissolved it in at least one selected from the group consisting of TiOCl2, TiCl4 and HCl.

The relative acidity, A, after dissolution in step a)may be in the range l-2.

The relative acidity, A, after dissolution in step a)may be in the range 2-3.

The relative acidity, A, after dissolution in step a)may be in the range 3-4.

The relative acidity, A, after dissolution in step a) in the range 5-7.

In a particular embodiment the relative acidity, A is in the range 7-9. l0 33 The content of ions in the dispersion obtained in stepa) may be decreased in optional step bl), preferablysuch that the ion concentration is lowered to a pointwhere a sol is formed. This can be achieved by one ofa combination of the following methods employingfiltration, dilution, ultrafiltration dialysis, diafiltration, cross flow filtration.In other words, the content of ions in the dispersionis decreased in optional step bl) preferably such thatthe ion concentration is lowered to a point where asol is formed wherein the average diameter of the particles in the sol is 3-20 nm, preferably 4-l5 nm,more preferably, 4.5-7 nm.

The sol obtained after steps bl) and b2) comprises at least 50 wt% titanium dioxide. In order to obtain concentrations approaching 50 wt% titanium dioxide andover it is in general necessary to decrease the content of ions according to optional step bl. If thecontent of ions is decreased the amount of titanium dioxide can be higher such as 60 and 70 wt % TiO2.

The pH of the dispersion of particles obtained afterstep b), or the sol obtained after steps bl and/or b2)may be adjusted to a value in the range 0.5-9. The pHadjustment makes it easier to handle and store the intermediate product.

The dispersion obtained after step b2 may be at least 50 wt% titanium dioxide. The dispersion obtained after step b2 may be up to 80 wt% titanium dioxide. 34 The sol obtained after steps bl) and/or b2) may be taken directly to step c) without drying andredispersion before step c).

Alternatively, a sol obtained after steps bl) and/orb2) may be dried and redispersed before step c). Anacidic and or alkaline stabilizer (as discussed below)helps to preserve the dispersed state of the particlesduring redispersion and counteracts irreversibleaggregation when the sol is dried down to a solid orpowder prior to redispersion.

Typically, the specific surface area measuredaccording to ISO 9277 of the particles dried from asol obtained after step bl) and/or b2) 200-300 m?/g. is in the range In one embodiment, the dispersion obtained after step b2) or after steps bl) and b2)comprises a sol of at least 15 wt% titanium dioxide, preferably at least 25 wt% titanium dioxide, more preferably at least 30 wt% titanium dioxide, even more preferably at least 40 wt%titanium dioxide, and most preferably at least 50 wt%titanium dioxide. The high concentration improves theand the method makes it possible which yield after step d)to use a high concentration of TiO2 particles,in turn can give a higher yield after step d).Further, in expensive hydrothermal reactors which canbe used for the process, especially in large scale, itis possible to have a larger amount of titaniumdioxide particles in each batch making the process to manufacture a structure of a titanium compound selected from the group consisting of sheets, wires and tubes more economical.

In one embodiment, no transition metal ions except titanium are added in steps a) or b). It is anadvantage that no metal ions have to be added since it simplifies the process and reduces the cost.

The dispersion obtained after step b) or b2) may be subjected to ion reduction step bl) to obtain an intermediate product.

The dispersion obtained after step b) or step bl) may be subjected to a concentration step b2) by one or acombination of methods selected from vacuum drying,settling and decantation, centrifugation, filtration, such as e.g. ultrafiltration, cross flow filtration, tangential flow filtration, and nanofilterationFurthermore, according to the present disclosure, analternative method for manufacturing a structure of atitanium compound selected from the group consistingof sheets, wires and tubes is provided. The methodcomprising the steps of i) providing a sol of particles comprisingTiO2, wherein the average diameter of the particles inthe sol is 3-20 nm, preferably 4-15 nm, 4.5-7 nm, morepreferably, and wherein the sol comprises atleast one acidic stabilizer; c) adjusting the concentration of hydroxideions in the sol to at least 8 M by adding an alkali metal hydroxide MOH; 36 d) treating the sol at a temperature in theinterval 90-170 °C during 6-72 hours to obtain aplurality of first structures comprising alkali metaltitanate; and e) treating the plurality of first structuresto exchange at least a part of the alkali metal ionsM* with H* to obtain a plurality of second structures comprising protonated titanate. may be obtained by the stepsand b2) The sol provided in step i) a) and b), optionally followed by steps b1) and modifications of these steps as described above.

By using a stabilizer in the dispersion obtained after step b, or in the sol obtained after steps bl) and/or b2), or in the sol provided in step i), the surfacesof the TiO2 particles are coated or partially coatedby molecules of the stabilizer, and this is believedto keep the particles from irreversible aggregationand condensation via interparticle Ti-O-Ti bondformation particularly as the sols become more andmore concentrated during step b2 or in subsequent stepc, or at least reduce the probability for aggregationand irreversible condensation. For citric acid as a stabilizer, and similar acidic stabilizers, and for monoethanolamine and similar alkaline stabilizers, thestabilisation of TiO2 dispersions is believed to beboth steric and electrostatic, depending upon the solution conditions. In a highly concentrated NaOHdispersion or sol of TiO2 as obtained as disclosedherein, the Debye length for electrostaticstabilisation is likely of such a short length that van der Waals or dispersion forces can aggregate TiO2 lO 37 particles. It is believed that the surface adsorbedstabilizer molecules stabilize the particles againstirreversible formation of interparticle Ti-O-Ti bondsin strong electrolytes where the Debye length is veryshort due to the steric stabilisation offered by thesurface adsorbed citric acid molecules. It is believedthat this steric stabilisation allows for fasterkinetics of the TiO2 to Na-titanate reaction relativeto non-sterically stabilised sols of similarconcentration and particle size due to the relativeease of diffusion of reactants into the interparticlespaces.

Moreover, the inventors have discovered that when TiO2sols obtained by a method as disclosed hereincomprising acid or base stabilizers are concentratedto a solid form and then redispersed in water, they reform a sol, where the particle size distribution in the liquid does not change to any noticeable extent.This means that the particles do not irreversiblyThus, aggregate. the stabilizer gives a better and easier redispersion.

An alkanolamine and at least one acidic stabilizer maybe added together before step c). If an alkanolamineis added as a stabilizer before step c), then it ispreferably added together with at least one acidic stabilizer.

The at least one acidic stabilizer may be at least oneselected from a carboxylic acid, and an alpha hydroxy acid. 38 The at least one acidic stabilizer may comprise at least one selected from the group consisting of, butnot limited to citric acid, and lactic acid.

The at least one alkanolamine may be at least oneselected from monoethanolamine, triethanolamine. It is believed that the at least one alkanolamine can act asa stabilizer of TiO2 particles in alkaline or basic pHdispersions, thus the at least one alkanolamine may beconsidered to be a stabilizer of TiO2 basic or alkaline conditions.

The concentration of hydroxide ions may be adjusted in step c) using NaOH, i.e. the alkali metal hydroxide is NaOH.

During step c) or before step d), i.e. during orimmediately after adjusting the concentration ofhydroxide ions in the dispersion or sol to at least 8 Mby adding an alkali metal hydroxide MOH, the dispersionor sol may be stirred and/or agitated and/or sonicated.When the pH is increased to such a large extentdispersion or the sol often becomes turbid and theviscosity may increase. Stirring and/or agitation and/orsonication is then suitable. Stirring and/or agitationand/or sonication is particularly advantageous forobtaining a homogeneous dispersion or sol during orimmediately after step c) when the concentration of theTiO2 dispersion or sol obtained is significantly higherthan 15wt%. It is believed that this stirring ofconcentrated dispersion or sols with at least 8M NaOH ismore effective for obtaining a homogeneous dispersion or sol prior to heating at 90-170 °C compared with stirring lO 39 powders of pure TiO2 which do not as readily disperse inthe same concentration of MOH, such as e.g. NaOH.

Nonetheless, stirring and/or agitation and/or sonicationis preferred for maximizing the homogeneity of the dispersion during step c).

Stirring may be performed during step d). The stirringis optional and affects the obtained first structuresobtained from step d). Stirring in general promotes formation of longer tubes. Additionally, stirring at this stage gives a more homogenous mixture, which inturn gives a more homogenous end material. Thestirring during step d) may include mechanicalstirring via use of a dedicated stirring reactor vessel or may include agitation of the entire reactionvessel by a rocking or rolling or shaking mechanism or by acoustic waves.

Suitably, the pressure in step d) is autogenous pressure. In other words, the treatment of the sol in step d) is performed at autogenous pressure.

Further, at least step d) may be carried out in a sealable reactor. Autogenous pressure is the pressurethat arises in a sealed reactor at a specific filllevel and temperature and can be estimated using steamtables and knowledge of the thermophysical propertiesof the reactants. A sealed vessel is necessary toreach temperatures above the boiling point. Then thepressure is increased compared to ambient pressure.The exact pressure is not critical as long as the desired temperature can be reached. lO Alternatively, an open container at ambient pressuremay be used for step d)and then it is suitablycombined with a reflux vessel to avoid excessive water evaporation.

The plurality of first structures comprising alkalimetal titanate obtained after step d) may be separatedfrom the remaining liquid between steps d) and e).This can be performed by filtration or by other meanssuch as centrifugation. Water may be added to theseparated comprising alkali metal titanate after theseparation.

Suitably, the plurality of first structures comprisingalkali metal titanate obtained after step d) areseparated from the mother liquor by a method that is not limited to, for example filtering before step e).

The alkali metal cations M* of the first structurecomprising alkali metal titanate obtained after step d) may be exchanged with H* to a ratio Ti/M calculatedby atomic percent of 6 or above. This is performedduring step e) and results in a second structurecomprising protonated titanate. The ratio is measuredin the second structure or subsequently formed third structure.

A second structure obtained after the ion exchange in step e) often comprises stacked layers. During the ionexchange the stacked layers do not appear to fullydelaminate to single layers, but can continue towards full demimation. If a high Ti/M ratio is used, thenthe delamination proceeds towards a more complete state during heating when the third structure 41 comprising titanium dioxide is obtained. During the ion exchange in step e) some delamination of stackedlayers occur and this process continues during thesubsequent heating of step f). The evidence from Fig17 indicates the process is greatly facilitated if a Ti/M ratio of 6 or above is used.

The plurality of second structures comprising protonatedtitanate obtained after step e) are suitably separated from the mother liquor by for example filtration after step e). Separation using combinations of relativetiming, including separation before, during and afterstep e) are also envisaged. During such a separation the structures can be recovered and at least partially redispersed in an aqueous solution.

The plurality of second structures comprising protonated titanate obtained after step e) may beheated in an optional step f)700 °C, preferably 300 - 600 °C, 450 °C, to a temperature in themore 400 °C range 300 -preferably 300 - most preferably 300 -to obtain a plurality of third structures comprising titanium dioxide.

The third structures typically comprise at least oneselected from the group consisting of sheets, wiresand tubes. The third structures may comprise TiO2(B).

The heating in step f) both provides TiO2(B) and removes organic impurities such as a stabilizer. l0 42 If it is desired to remove the stabilizer entirelystep f) should preferably be performed in air or with other agents known to aid oxidation.

In some instances it may be desirable to heat thefirst or second structures comprising alkali orprotonated titanate in an atmosphere and temperaturesuch that the said heating results in formation of acarbon-TiO2(B) hybrid, for example when propertiessuch as conductivity is desired to be combined at anintimate molecular level, such as for the manufactureof Li-ion battery anodes, where a conductive materialcomprises the anode along with other components including a lithiated TiO2(B).

The third structure comprises titanium dioxide and iswherein the second structure is 700 °C, obtained in step f)heated to a temperature in the range 300 -preferably 300 - 600 °C,450 °C, more preferably 300 - 600 °C,most preferably 300 -- 400 °C. even more preferably 300The Ti/M ratio is calculated by taking the O atomic 6 of Ti in the the second or in the third structure, (the said atomic ratio is assumed to bestable on going from the second to third structure, so it can be measured in either one) and dividing it by O the atomic 6 of the M in the respective second or third structure. A ratio above 6 as can be seen in Fig9 to correlate with a higher specific surface areaafter heating. Without wishing to be bound by anyparticular scientific theory, the inventors believethat a higher Ti/M facilitates delamination of stackedlayers during acid exchange of M* by H* on going from layered alkali metal titanate (e.g. sodium titanete) lO 43 to layered protonated titanates. This delamination ofstacked layers for such relatively low M*-containingsecond structures may continue to occur during heatingof the second structures to the third structures, asindicated by the decrease in intensity of the (002)XRD peak on going from llO°C to 350°C seen in Figuresl, 3, 5 and 7. Some of the structures obtained afterstep c) comprise stacked layers.The first, second and third structures denote mutuallydistinct structures. The first and second structuresare typically compositionally distinct layered of the titanates, because the alkali metal ions M* first structure are replaced, at least partially, byH* in the second structure, typically yielding adifferent dæom crystallographic spacing betweenlayers, and often less intensity and more broadening of the XRD peaks indicative of relatively smaller or less well ordered crystallographic arrangements of theatoms, at least in part due to delamination and curvature induction.

The third structure is distinct from the first andsecond structures since it has undergone substantialdehydration, layer condensation and atomicrearrangements to form at least a fraction of TiO2(B),wires and which can be stable in thin sheets, tubes, other nanostructured forms, but does not have aformally layered crystal structure as do the first twostructures whose Ti and O atoms are not bonded across the layer space.

The present disclosure also provides an intermediate product obtained after step b), bl) and/or b2), said 44 intermediate product being a dispersion or sol of particles comprising TiO2 and comprising at least oneacidic stabilizer. The intermediate product is adispersion or sol of particles comprising TiO2 and thefirst, second and third structures obtainable by amethod according to the present disclosure are made of such particles.

The intermediate product obtained after step b), bl) and/or b2) can be stored, transported and handled easily before the structures such as sheets, tubes and wires are made. This intermediate product can be stored for extended periods such as weeks to years, making a large scale process easier.

The pH of the intermediate product may be in the range 0.5 - 9.

The intermediate product may comprise at least 15 wt% TiO2, preferably at least 17 wt% TiO2, more preferably at least 25 wt% TiO2, even more preferably at least 30 wt% TiO2, preferably at least 50 wt% TiO2, and most preferably at least 50 wt% TiO2. Up to slightly in excess of 40 wt%, it is still a sol. If ion removal is performed in step b1, the resulting sol can have over50 Wtoñ TlÛg.

The intermediate product obtained from step b, b1)and/or b2) may be concentrated by drying under vacuumso that the concentration of titanium dioxide is at least 50 wt%.

The concentration of titanium dioxide in the intermediate product obtained after steps b) bl) l0 and/or b2) may be at least 70 wt%. In such cases the intermediate product is viscous sol.

The specific surface area measured according to ISO9277 of the TiO2 particles dried from the dispersionof the intermediate product obtained after steps b) bl) and/or b2) is in the range 200-300 m2/g.

The present disclosure also provides a third structurecomprising titanium dioxide, said third structure being one of a sheet, a wire, and a tube, said structure obtained after step f) as described above.

The third structure may comprising sheets, wires andtubes may constitute a part of a lithium ion batteryanode. Advantages of using said third structures of TiO2(B) comprising sheets, wires and tubes is theability for Li ions to readily insert/extract in/fromthe open framework in the TiO2(B) unit cell at aconcentration up to an atomic Li/Ti ratio maximum of lwith little change to the crystal structure. This inpart allows inherently and relatively fast charge anddischarge rate compared with typical graphite anodes used in Li ion batteries, and with an attractive theoretical capacity of 335 mAh.g*. Further, this verylow expansion and contraction of the bronze unit cellduring Li transport in and out of the TiO2(B) crystalsduring charging and discharging respectively equateswith enhanced dimensional stability of an anodecomprising TiO2(B). This is evident by looking at thestate of the art on lithium TiO2(B) crystal structures- for example in Armstrong et al., 6426-6432 (20l0) Chemistry ofMaterials 22, where they reported crystal structures of lithium-free TiO2(B), lO 46 Ll0_25TlO2 (B) Ll0_5TlO2 (B) , LlggTlog (B) and Ll0_9TlO2 (B) .The volume of the unit cell expands up to a maximum8.4% over the structure of bulk, lithium-free TiO2(B).

The dimensional stability of TiO2(B) as an anodematerial during charging and discharghing is anattractive feature that can equate to enhanced longterm cycling stability and significantly longerbattery lifetimes.

Additionally, said third structures comprisingtitanium dioxide sheets, tubes or wires can form anetwork when a plurality of individual structures iscondensed to a solid material, such as in a film of finite thickness. Further, such networks of a plurality of said third structures of TiO2, cancomprise a significant interconnected mesopore networkbetween the individual structures making up theplurality of individual structures.

Further, the third structures comprising titaniumdioxide sheets, tubes or wires can form a network withrelatively long conductive paths combined withrelatively short transport paths from Li ion bindingsites in the crystals from the electrolyte all ofwhich enhance the kinetics and capacity of the anoderelative to one comprised of uniformly dimensioned particles of the same crystal structure.

To make an anode from the said third structurescomprising titanium dioxide sheets, tubes or wires itmay be desirable to form a network comprising aplurality of individual structures condensed to a solid material, such as in a film of finite thickness, lO 47 the said network also comprising a significantinterconnected mesopore network between the individualstructures making up the plurality of individualstructures. Such a desirable network structure in theform of a film can be made from previously undriedsuspensions of second structures comprising protonatedof the method titanates, obtainable after step e) disclosed herein, by a variety of methods including casting, blade coating, spin coating, spraying, electrospraying, dipping onto various substratesincluding metal foils, and then subjecting the saidfilm to step f) as disclosed herein to form a thirdstructure comprising titanium dioxide and selectedfrom the group consisting of sheets, a wires andtubes. Such a desirable network structure canalternatively be formed by subjecting previously constructed films of TiO2 nanoparticles to one or more of the steps c-f disclosed herein.

Together the said advantages of using third structures of TiO2(B) comprising sheets, tubes or wires tocomprise an anode in a Li ion battery include fastcharge and discharge rates, high current capacity,high dimensional stability, long term cycling performance and long battery lifetime.

The structure of a titanium compound manufacturedaccording to the steps disclosed herein may constitutea part of an anode of an all solid state lithium ionbattery. The structure may be a sheet, tube or wire.

The structure of a titanium compound manufactured according to the steps disclosed herein may constitute 48 a part of an anode of a solid state lithium ion microbattery. The structure may be a sheet, tube or wire.

The structure of a titanium compound manufacturedaccording to the steps disclosed herein may constitutea part of an anode of a solid state battery. Thestructure may be a sheet, tube or wire.The structure of a titanium compound manufacturedaccording to the steps disclosed herein may constitutea part of an anode of a lithium sulfur battery. Thestructure may be a sheet, tube or wire.The structure of a titanium compound manufacturedaccording to the steps disclosed herein may constitutea part of an anode of a lithium oxygen battery. Thestructure may be a sheet, tube or wire.The structure of a titanium compound manufacturedaccording to the steps disclosed herein may constitutea part of an anode sodium ion battery. The structuremay be a sheet, tube or wire.A carbon hybrid structure of a titanium compoundmanufactured according to the steps disclosed hereinmay constitute a part of an anode of an alkali metaltube or ion battery. The structure may be a sheet, wire.

The structure of a titanium compound manufacturedaccording to the steps disclosed herein may constitutea part of a photocatalytic object or device. The stucture may be a sheet, tube or wire. lO 49 The intermediate product obtained after steps b, bl orb2 may constitute part of a photocatalytic object ordevice or is used as a precursor dispersion for making said photocatalytic object or device.

The intermediate product obtained after steps b, bl orb2 may constitute part of an anode of a lithium ionbattery or may be used as a precursor dispersion for making said anode of a lithium ion battery.

ExamplesThe invention is further described by the following examples.

Example l. An acidic, lO wt% TiO2 dispersion of pH was prepared according to step a) and step b), bymixing 2.5 parts of titanic acid suspended in water(22-24 wt % TiOh with l part of TiOCl2 solution density l.5-l.6 g.cm*) to obtain a clear solution(step a)) and adding citric acid as stabilizer in massratio of lO:l TiO2: citric acid prior to raising thetemperature to 80°C and holding for 75 minutes (stepb)) and subsequent rapid cooling. The said titanicacid suspended in water was pH 5.5 and was preparedbefore step a) by mixing 2 parts of said TiOCl2 solution with l part of water and 8.8 parts lO% NaOH,keeping the temperature in the range 25-40°C. In this example, the ratio of two masses, i.e., the mass of Ti in the aqueous TiOCl2 solution used to prepare thetitanic acid suspended in water and the mass of Ti inthe aqueous solution of TiOCl2 that was mixed withtitanic acid in step a) to form a clear solution was 3:7.

After step b),and b2)) the ion and water content were adjusted (steps bl) to pH 1 to 1.5 and 20 wt% TiO2 so that an acidic sol of TiO2 was obtained.Example 2. An alkaline sol of pH 8.5-9.0 with 15 wt %TiO2 was prepared before step c) by taking the 20 wt %acidic sol of pH 1 to 1.5 of Example 1 and addingwith citric acid, KOH and monoethanolamine (MEA) stirring To 6.1 parts of the acidic sol thefollowing were added - 1 part of a basic solutioncomprised of 1.8 parts water, 1.8 parts of KOH (49wt%) and 1.0 parts citric acid. MEA was added so thefinal mass of the final alkaline sol had a mass ratioof citric:MEA of 2.1:1.

Example 3. The acidic dispersion obtained after step step b) in Example 1 was concentrated (step b2)) withrespect to TiO2 content by differential densityseparation, such that from the 2.2 parts by weight ofthe dispersion obtained after step b), 1.0 part of aclear liquid was removed, the said clear liquid beingsubstantially free of TiO2particles, leaving 1.2 partscomprising TiO2 particles as a concentrated whitepaste and residual clear mother liquor. Following thisconcentration step, the said 1.2 parts was thendiluted with the said 1.0 parts of water whichcorresponds to step b1, whereby a total of 2.2 partsof an ion-reduced acidic dispersion of TiO2 wasobtained with pH < 0.

TiO2 was Example 4. An acidic dispersion of 20 wt% obtained by subjecting the said ion-reduced dispersion of TiO2 from Example 3 to diafiltration (step b1)) and ultrafiltration (step b2)), where the said 2.2 partsof ion-reduced acidic dispersion of example 3 plus 1.4parts of water were added as inputs to obtain 0.7 TiO2 parts of 20 wt% acidic sol of pH 1-1.5 and 2.7 parts produced water.Example 5. The acidic sol from example 4 wasevaporated to a solid form under vacuum (step b2)) sothat the said solid form was redispersible in water The such that a stable TiO2 sol was thereby obtained. weight percentage of TiO2 in the sol formed byredispersing the said solid could be tuned by varyingthe ratio of water to said solid. In this case a finalsol of 40 wt% TiO2was obtained from redispersing thesaid solid.Example 6. The alkaline sol of Example 2 wasevaporated under vacuum while heating at 60 °C b2)) (step O to obtain a sol with a TiO2 content > 15 6. Inthis way the said alkaline sol of Example 2 was concentrated to 37 wt% TiO2.

Example 7. The said alkaline sol of Example 6 was diluted with water to obtain a sol of 30 wt% TiO2.

Example 8. The 20 wt% TiO2 sol of example 1 was pH adjusted with 10 M NaOH (step c)) according to the amounts and conditions of Exp # JAT-1-019 of Table 1.Explicitly, 0.477 g of said sol was well mixed with 0.19 g of 10 M NaOH (step c))and was heated under autogeneous pressure in a Teflon-lined steel autoclaveat 130°C for 24 hours (step d)) to form a sodium titanate product. This product was then ion exchanged with 0.1 M HCl (step e)), washed and dried in air at room temperature. The said product was characterised using transmission electron microscopy (TEM) and the results appear in Table 2.

Example 9. A 15 wt% TiO2 sol prepared according to Example 2 was used as a reactant along with 2-15 M NaOH (step c))according to the amounts and conditions given in Table 1 for all experiments where the entry in the column marked *% TiO2 in sol' is stated as 15%.

As in Example 8, the reactants for each experiment were mixed and heated (step d)) in an autoclave under the conditions given in Table 1 to produce sodium titanate products. The said sodium titanate products were then ion exchanged (step e)) to obtain protonated titanates, then washed and dried in air at room temperature and split into fractions that weresubsequently heated to either 110°C in air for 2.5 hours or 110 °C in air for 2.5 hours followed by heating in air to 350°C for 2.5 hours (step f)). The said products were then characterised by one or more of the following: X-ray powder diffraction (XRD), Raman spectroscopy, nitrogen physisorption scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive x-ray analysis (EDX) or thermogravimetric analysis (TGA).

Example 10. A 37 wt % TiO2 sol prepared according to Example 6 was used as a reactant along with 10 M NaOH(step c)) according to the amounts and conditionsgiven in Table 1 for all experiments where the entry in sol' is stated as 37%. in the column marked *% TiO2 As in Examples 8 and 9, the reactants for eachexperiment were mixed and heated in an autoclave underthe conditions given in Table 1 to produce sodium titanate products (step d)). The products were subsequently treated by the same processes (step e),heating at 110°C and step f)) and characterisationmethods as the products of Examples 8 and 9 after being removed from their respective reaction vessels.A 30 wt % TiO2 Example 11. sol prepared according to Example 6 was pH adjusted with 10 M NaOH (step c))according to the amounts and conditions given in Table1 for all experiments where the entry in the column As in TiO2 in sol' is stated as 30%. 9 and 10, marked “% Examples 8, the reactants for each experiment were mixed (step c)) and heated in an autoclave (step d)) under the conditions given in Table 1 to produce sodium titanate products. Theproducts were subsequently treated by the sameprocesses (steps e), heating at 110°C and f)) andcharacterisation methods as the products of Examples8, 9 and 10 after being removed from their respective reaction vessels.

Example 12. 2.8969 mg of sample RWC-1-24 obtained after step e)(see Table 1) was heated at 110°C for 2.5 hours in air and subsequently subjected to thermogravimetric analysis (TGA) where it was heated at 20° C per minute from room temperature to 500° C inflowing nitrogen gas, and the weight loss recorded as17.2%. The sample after heating was a black powder indicative of the formation of carbon-TiO2(B) hybrid material comprising tubes, where the carbon was sourced from the residual organics remaining afterformation, washing and drying of the protonated titanates in this sample.

Fig 1 shows X-ray powder diffraction (XRD) patterns corresponding to the product of heat treating (i.e.step f)) the plurality of second structures obtainedfrom experiment RWC-1-018 of Tables 1 and 2. Bothpatterns are indexed according to a monoclinictitanate crystal structure of composition (H, Na)2Tiﬂh, following the indexing given in Carvahlo et al., Chemical Engineering Journal 313 (2017) 1454- 1467. The peaks labelled with an asterisk in the upperpattern are indexed to TiO2(B), according to theACS Nano 8(2) (020) indexing given in Etacheri et al., 1491- 1499 (2014). Note that the (110) and peaks are common to both structures. The relative area under the (200) or (O01*) peaks is taken as an indicator of the degree of delamination (de-stacking) of the sheet structure (or the TiO2(B) sheets/tube walls formed from it, so that any peak intensity is taken toindicate some degree of stacking of the titanate phaseor the relative thickness of the TiO2(B) sheet formedfrom it. The relative level of stacking of layers (or TiO2(B) sheet thickness) can be compared between this and other samples in Table 2. Thinner TiO2(B)sheetsare desirable in some cases where a higher specificand surface area is desirable. As is seen in Table 2, in Figure 9, larger peaks (corresponding to thicker TiO2(B) sheets/tube walls) correlate with lower BET areas, and that the highest BET specific surface areasare obtained when the Ti/Na atomic ratio is highest.

This implies that delamination of the titanate sheets is more effective when the ion exchange process (i.e.step e)) removes enough Na so that the Ti/Na atomicratio is approximately larger than 6. Below thislevel, stacks of titanates remain and form thickerbronze sheets with lower specific surface area. Asshown in Table 2, this sample shows low sodiumindicative of a high degree of ion exchange to protons (hydronium ions)during step e).

Fig 2 shows Raman spectra of the same samples in Figure 1. In the case of these and the other Raman spectra shown herein, the spectra are taken not from the whole sample but from 5-10 micrometer spots within the sample and some variation occurs, consistent with some local variation possibly due to different polymorphs of the titanate. The lower curve at 110 °C is assigned to a titanate structure in accordance with the assignments of Carvahlo et al., Chemical Engineering Journal 313 (2017) 1454-1467. The upper curve is assigned to a TiO2(B) structure according to the assignments of Feist et al., Journal of Solid State Chemistry 101, 275-295 (1992).

Fig 3 shows X-ray powder diffraction (XRD) patterns corresponding to the product of heat treating (step f)) the plurality of second structures obtained from experiment RWC-1-019 of Tables 1 and 2. Both patterns are indexed according to a monoclinic titanate crystal structure of composition (H,Na)2Ti¿%, following the indexing given in Carvahlo et al., Chemical Engineering Journal 313 (2017) 1454-1467. In addition, peaks with single asterisks mark the expected position of TiO2(B) peaks and those with double asterisks mark the positions expected for TiO2 anatase. The lower curve is consistent with titanate. The upper patternis consistent with TiO2(B) that is transitional to, orco-mixed with TiO2 anatase. The presence of anatase is also indicated in Figure 4.

Fig 4 shows Raman spectra of the same samples in Figure 3. The lower curve at 110 °C is assigned to atitanate structure in accordance with the assignmentsof Carvahlo et al., (2017) 1454-1467.

Chemical Engineering Journal 313The upper curve is assigned to TiO2anatase.

(XRD) Fig 5 shows X-ray powder diffraction patterns corresponding to the product of heat treating (stepf)) the plurality of second structures obtained fromexperiment RWC-1-022 of Tables 1 and 2. Both patternsare indexed according to a monoclinic titanate crystal(H,Nä)2Ti3Û7, structure of composition following the indexing given in Carvahlo et al., Chemical Engineering Journal 313 (2017) 1454-1467. In addition,peaks with single asterisks mark the expected positionof TiO2(B) peaks. The lower curve is consistent with titanate. The upper pattern is consistent with TiO2(B).

Fig 6 shows Raman spectra of the same samples in Figure 5. The lower curve at 110 °C is assigned to atitanate structure in accordance with the assignmentsof Carvahlo et al., (2017) 1454-1467.

Chemical Engineering Journal 313The upper curve is assigned to atitanate that is barely transitional to TiO2(B) structure according to the assignments of Feist et al., Journal of Solid State Chemistry 101, 275-295 (1992), in particular we believe this is indicated bythe 151 and383 448 increasing intensity of the peaks at 126, cm* and the onset of broadening of the peaks at and 660 cmﬂ.

Fig 7 shows X-ray powder diffraction (XRD) patterns corresponding to the product of heat treating (step f)) the plurality of second structures obtained from experiment RWC-1-024 of Tables 1 and 2. Both patterns are indexed according to a monoclinic titanate crystal structure of composition (H,Na)2Ti¿%, following the indexing given in Carvahlo et al., Chemical Engineering Journal 313 (2017) 1454-1467. In addition, peaks with single asterisks mark the expected position of TiO2(B) peaks. The lower curve is consistent withtitanate. The upper pattern is consistent withTiO2(B). Note that the 001 peak of TiO2(B) in the upper curve is approaching zero, consistent with anapproach to complete delamination of the titanate asconsistent with it converts to thin TiO2(B) sheets, the high surface area of this sample.

Fig 8 shows Raman spectra of the same samples in Figure 5. The lower curve at 110 °C is assigned to atitanate structure in accordance with the assignmentsof Carvahlo et al., Chemical Engineering Journal 313(2017) 1454-1467.

TiO2(B) The upper curve is assigned to structure according to Feist et al., Journal of Solid State Chemistry 101, 275-295 (1992).

Fig 9 shows the Ti/Na ratio measured from EDX (see Table 2) versus the BET surface area of the 350 °C treated samples, as discussed in the caption to Figure 1. There appears to be a correlation between a high degree of delamination, as indicated by high surface areas and the ratio of Ti/Na measured in the ionexchanged product. It appears that achievingrelatively higher degrees of delamination occurs abovea Ti/Na ratio of approximately 6. Note that the datapoint with a surface area close to 200°C can beconsidered an outlier here, since its crystal structure is TiO2 anatase, whereas all the other data points correspond to TiO2(B)Fig 10 shows an SEM image of sample RWC-1-005, withwell formed elongate aggregated clusters of tubes/rodsforming a porous solid.

Fig 11 shows a TEM image of sample RWC-1-005, withwell formed tubes forming an open structured web ornetwork of varying degrees of compactness likelyinduced by the TEM sample preparation.

Fig 12 shows a TEM image of sample RWC-1-017, withwell formed long tubes forming an aggregate ofparallel tubes, surrounded by shorter pieces of tubes,many likely broken during the grinding and sonicationused in sample preparation. The tubes are clearlyhollow here, with outer diameters of approximately 5nm, inner diameters of the order of 1.5-2.0 nm andwall thicknesses of approximately 1.5 nm. The innerand outer tube diameters of typical tubes obtainedare 1.5-8 nm and 5-10 nm, after step e) respectively. sample RWC-1-018 obtainedl10°C, Fig 13 shows an SEM image of after step e) and heating at with well-formed elongate, curved and twisted tubes/rods forming an aggregated porous solid. The nitrogen physisorption experiment performed on this sample revealed amesopore volume of approximately 0.6-0.65 cm3.g* and atight mesopore size distribution on adsorption anddesorption centered near 8 nm, illustrating that thisaggregated assembly of tubes was likely homogeneous onthe macroscopic scale and that the aggregatedstructure forms mesoporous solid with a well defined and accessible internal mesopore system. sample RWC-1-020 obtainedl10°C, Fig 14 shows an SEM image of after step e) and heating at with well-formed elongate, curved and twisted tubes/rods forming an aggregated porous solid. sample RWC-1-024 obtainedl10°C, Fig 15 shows an SEM image of after step e) and heating at with well-formed elongate, curved and twisted tubes/ribbons forming an aggregated porous solid.

Fig 16 shows a zoomed in view of the SEM image of sample RWC-1-024 obtained after step e) and heating at 110°C, seen in Figure 14, clearly showing the diameter of individual tubes/ribbons as approximately 3-8 nm.

Figure 17 shows the adsorption (squares) and desorption (diamonds) branches of the nitrogen physisorption isotherm at 77 K corresponding to JAT-1- 017 after step f) of Tables 1 and 2.

Figure 18 shows the BJH desorption pore size distribution derived from the desorption branch ofFigure 17. The inner hollow space of the tubes can beconsidered as a long cylindrical pore. The peak in thepore size distribution at 3.4 nm is interpreted as themean inner pore radius of the tubes, corresponding toan inner pore diameter of 6.8 nm. The pore volume inpores corresponding p/po approximately 0.99 for thissample was O.4625 cm3.g*. The BJH pore sizes determined by nitrogen physisorption Table 1 shows conditions for the examples.

Table 2 shows results from the examples.

Table l Input conditions 61 EXP # Temperature mass Ti02 % Ti02 in mass heating OHsol sol Ti02 time molarity RWC-1-005 120 1,200 15 0,180 19 9,9RWC-1-006 90 2,520 15 0,378 18 9,9RVVC4=007 98 4,800 15 0,720 19 9,9RWC-1-008 130 2,470 15 0,371 16 9,2RWC-1-009 130 2,400 30 0,720 24 9,8RWC-1-010 100 2,400 30 0,720 24 9,8RWC-1-011 100 2,400 30 0,720 24 10,2RWC-1-012 130 2,400 30 0,720 20 9,8RVVC4=013 130 4,800 15 0,720 70 8,1RWC-1-014 130 1,200 30 0,360 46 10,2RWC-1-015 100 1,200 30 0,360 46 10,5RWC-1-016 100 2,400 30 0,720 46 10,2RWC-1-017 145 2,400 15 0,360 47 9,2RWC-1-018 100 2,400 30 0,720 46 10,2RWC-1-019 100 9,600 15 1,440 46 8, 1RWC-1-020 145 1,501 30 0,450 22 10,2RWC-1-021 145 3,200 15 0,480 19 9,2RWC-1-022 145 2,480 37 0,918 27 10,4RWC-1-023 145 2,457 37 0,909 27 10,4RWC-1-024 145 2,426 15 0,364 27 9,4RWC-1-026 130 2,400 15 0,360 19 9,9RWC-1-027 130 2,420 15 0,363 19 9,9RWC-1-028 162 2.480 37 0.918 18 10,5RWC-1-029 162 2.964 30 0,889 18 10,2JÅT4=002 130 1,210 15 0,182 22 10,1JÅT4=003 130 1,220 15 0,183 7 10,11ÅT4=004 130 1,210 15 0,182 7 10,1JÅT4=005 130 1,210 15 0,182 7 10,1JÅT4=006 130 1,221 15 0,183 22 10,1JÅT-1-007 130 2,447 15 0,367 22 9,2JÅF1008 130 6004 15 Q901 22 'Z7JÅT-1-009 130 8,406 15 1,261 22 6,9JÅT4=010 130 1,215 15 0,182 20 3,8JÅT4=011 130 1,219 15 0,183 20 5,8JÅT-1-012 130 1,245 15 0,187 20 7,7JÅT4=013 130 1,219 15 0,183 20 16,5JÅﬂ*I015 115 1,202 15 0,180 8 9,9JÅT4=016 115 1,222 15 0,183 24 9,91ÅT4=017 115 1,219 15 0,183 36 9,9JÅF1018 130 6000 20 L200 24 'Z4JÅT-1-019 130 0,477 40 0,191 24 10,5 62 JAT-1-021 130 12,070 1,811 24 9,9 63 Table 2 Results Exp EM texture EDX EDX BET XRD XRD XRD XRD# texture length Ti Na S.A phase phase d(200) d(200)nm . 110°C 350°C 350°C 350°Cm2/ peak peakg area widths.d.RWC- tubes to 25-250 24,1 7,05 titanate titanate1- well 5 /TiO2(B)005 formedtubesRWC- open 50-200 15,5 14,5 titanate titanate1- tubes to 1 3 /TiO2(B)006 sheetsRWC- tubes to 50-200 21,1 8,42 titanate titanate1- open 2 /TiO2(B)007 tubesRWC- tubes, 50-200 16,0 15,7 titanate titanate1- open 9 3 /TiO2(B)008 tubesandcurledsheetsRWC- tubes to 100-200 28,8 11,4 titanate titanate 69,3 1,331- open 6 6 /TiO2(B)009 tubesandsheets 64 RWC- tubes to 100-200 titanate titanate 43,8 1,561- sheets /TiO2(B)010RWC- tubes to 25-50 46,6 7,82 titanate titanate 56,3 1,491- sheets /TiO2(B)011RWC- tubes or 25-100 24,7 6,55 172 titanate titanate 65,9 1,41- rods 4 /TiO2(B)012RWC- tubes to 25-100 22,9 10,5 117 titanate titanate 70,2 1,41- curved /TiO2(B)013 sheetsRWC- tubes to 25-50 22 7 221 titanate titanate 52,9 1,371- open /TiO2(B)014 tubesandcurvedsheetsRWC- sheets 25-100 21,2 12,1 titanate titanate 74 1,751- with 7 /TiO2(B)015 curlededges toopentubesRWC- tubes to 25-50 18 10,8 titanate titanate 52,4 1,571- sheets /TiO2(B)016 withcurled edges RWC- tubes 50-200 27,8 0,38 289 titanate titanate 14,4 2,831- 4 /TiO2(B)017RWC- tubes to 25-300 19,8 0,9 284 titanate titanate 27,7 2,981- ribbons 2 /TiO2(B)018 of tubesRWC- short 10-100 23,4 3,64 197 titanate titanate 32,3 2,981- tubes to 7 /TiO2019 curled anatasesheetsRWC- tubes 50-250 23,0 6,34 237 titanate titanate 49 1,261- 4 /TiO2(B)020RWC- tubes to 25-100 21,8 0,09 titanate titanate 16,7 2,211- well 8 /TiO2(B)021 formedtubesRWC- tubes to 50-150 28,1 4,49 291 titanate titanate 33,5 2,071- open 2 /TiO2(B)022 tubesRWC- tubes to 50-200 29,6 3,3 titanate titanate 44,1 1,471- well 8 /TiO2(B)023 formedtubesRWC- well 50-1000 22,0 0,14 282 titanate titanate 15,8 2,141- formed 5 /TiO2(B)024 tubes toopen tubes 66 RWC- tubes to 50-100 25,3 0,94 titanate Titanate1- open 1 /TiO2(B)026 tubes andsheets RWC- tubes to 50-100 23,7 0,05 titanate titanate1- open 8 /TiO2(B)027 tubes andsheets JAT- tubes 90-130 titanatel- 002 JAT- short 30-50 titanate1- tubes003 JAT- short 30-50 titanate1- tubes004 JAT- tubes or 30 titanate1- wires005 JAT- Sheets 20-30 amorphou1- and s006 ribbons/ tubes JAT- titanate l_ 007 67 JÄT-l_008 titanate JÄT-l_009 titanate JÄT-l_010 Sheets titanate JÄT-1-011 Sheets titanate JÄT-l_012 Sheets titanate JÄT-l_013 Sheets amorphous JÄT- 015 titanate JÄT-l_016 Mixtureofsheetsandshorttubes -40 titanate JÄT-l_017 tubes 90-130 titanate 68 JAT- mainly 201- sheets.018 SometubesJAT- Very 200-1- long 1000019 tubes200-1000nm inbundlesJAT- Agglomer 100-5001- ated021 tubes or ribbons

Claims

1. l. 69 Claims A method for manufacturing a structure of a titanium compound selected from the group consisting of sheets, wires and tubes, the method comprising the steps of: a)providing at least one titanic acid with the general formula [TiOX(OH)44X]n and dissolving it in anaqueous solution comprising at least one selectedand HCl from the group consisting of TiOCl2, TiCl@ so that a clear solution is obtained, wherein the pHof the clear solution is lower than l after dissolution, increasing the temperature of the clear solutionuntil reaching a temperature in the interval 68-85°C where precipitation starts to occur, adding atleast one acidic stabilizer before the precipitationstarts to occur, and holding that temperature duringat least l minute during stirring to obtain adispersion of particles comprising TiO2 as an intermediate product, adjusting the concentration of hydroxide ions in thedispersion from step b) to at least 8 M by adding an alkali metal hydroxide MOH, treating the dispersion from step c) at atemperature in the interval 90-170 °C during 6-72hours to obtain a plurality of first structures comprising alkali metal titanate, treating the plurality of first structurescomprising alkali metal titanate to exchange at least a part of the alkali metal ions M* with H* to obtain a plurality of second structures comprising protonated titanate.

2. The method according to claim l,furthercomprising, after step b) and before step c), thesteps of:bl) decreasing the content of ions in thedispersion preferably such that the ionconcentration is lowered to a point where a sol isformed, wherein the average diameter of theparticles in the sol is 3-20 nm, preferably 4-l5nm, more preferably, 4.5-7 nm; andb2) adjusting the concentration of TiO2 in thedispersion preferably to a value within the rangeof l0-80%, more preferably to a value within therange 20-70%, most preferably to a value within the range 30-50%.

3. The method according to l or 2, wherein thedispersion after step b) or the sol after steps bl)and b2) comprises at least l5 wt% titanium dioxide,preferably at least l7 wt% titanium dioxide, morepreferably at least 25 wt% titanium dioxide, even morepreferably at least 30 wt% titanium dioxide, and evenmore preferably at least 40 wt% titanium dioxide, and most preferably at least 50 wt% titanium dioxide.

4. The method according to any one of claims l-3,wherein the plurality of second structures comprisingprotonated titanate obtained after step e) are heatedto a temperature in the range 300 - 700 °C, preferably300 - 600 °C, more preferably 300 - 450 °C, mostpreferably 300 - 400 °C to obtain a plurality of third structures comprising titanium dioxide. 71

5. The method according to any one of claims 1-4,wherein the at least one acidic stabilizer is selected from a carboxylic acid, and an alpha hydroxy acid.

6. The method according to any one of claims 1-5,wherein at least one alkanolamine and at least one acidic stabilizer are added together before step c).

7. The method according to any one of claims 5-6,wherein the carboxylic acid is selected from the group consisting of citric acid, and lactic acid.

8. The method according to any one of claims 1-7, wherein stirring is performed during step d).

9. The method according to any one of claims 1-8,wherein the dispersion has remained in a dispersedstate without drying and subsequent redispersion between steps b) and c).

10. The method according to any one of claims 1-8,wherein the dispersion is dried and redispersed between steps b) and c).

11. The method according to any one of claims 1-10, wherein the specific surface area, as measuredaccording to ISO 9277 of the particles dried from thedispersion obtained after step b), is in the range 200-300 m?/g.

12. The method according to any one of claims 1-11, wherein the pH after dissolution in step a) is lower than 0. 72

13. l3. The method according to any one of claims l-l2, wherein the pH of the dispersion resulting fromstep b) or the sol resulting from steps bl) and b2) is adjusted to a value in the range 0.5-l.5.

14. l4. The method according to any one of claims l-l3, wherein the concentration of hydroxide ions is adjusted in step c) using NaOH.

15. l5. The method according to any one of claims l-l4, wherein the titanic acid provided in step a) ismade from a TiOCl2 by neutralisation until precipitation by an aqueous solution of NaOH.

16. l6. The method according to any one of claims l-l5, wherein the plurality of first structurescomprising alkali metal titanate are separated from the remaining liquid between steps d) and e).

17. l7. The method according to any one of claims l-l6, wherein the treatment of the dispersion in step d) is performed at autogenous pressure.

18. l8. The method according to any one of claims l-l7, wherein no transition metal ions except titanium are added.

19. l9. An intermediate product obtained after step b)in any one of claims l-l8, being a dispersion ofparticles comprising TiO2 and comprising at least oneacidic stabilizer and wherein the intermediate productoptionally exhibits one or more of the followingfeatures:- the dispersion comprises at least l5 wt% TiO@preferably at least l7 wt% TiO2, more preferably at least 25 wt% TiO2, even more preferably at 73 least 30 wt% TiO2, even more preferably at least40 wt% TiO2, and most preferably at least 50 wt%titanium dioxide; - the at least one acidic stabilizer is at leastone selected from a carboxylic acid, and analpha hydroxy acid; - the pH is in the range 0.5 - 9; - the specific surface area measured according toISO 9277 of the particles dried from the dispersion is in the range 200-300 m?/g.

20. An intermediate product obtained after steps bl) and b2) of any one of claims 2-18, being a sol of particles comprising TiO2 and comprising at least one acidic stabilizer and wherein the intermediate productoptionally exhibits one or more of the following features: - the sol comprises at least 15 wt% TiObpreferably at least 17 wt% TiO2, more preferablyat least 25 wt% TiO2, even more preferably atleast 30 wt% TiO2, even more preferably at least40 wt% TiO2, and most preferably at least 50 wt%titanium dioxide; - the at least one acidic stabilizer is at leastone selected from a carboxylic acid, and analpha hydroxy acid; - the pH is in the range 0.5 - 9; - the specific surface area measured according toISO 9277 of the particles dried from the sol isin the range 200-300 m?/g.

21. A structure comprising titanium dioxide, said structure being one of a sheet, a wire, and a tube, 74 said structure being made according to any one of claims 1-18.

22. The structure according to claim 21, whereinthe structure constitutes a part of a Li ion or sodium ion battery anode.

23. The structure according to claim 21, whereinthe structure constitutes a part of a photocatalytic object.

24. The structure according to claim 21, whereinthe structure constitutes a surface modification or treatment of a titanium dental or bone implant.