WO2019109171A1

WO2019109171A1 - Lithium-ion battery in the form of a flexible wire, process for manufacture and uses thereof

Info

Publication number: WO2019109171A1
Application number: PCT/CA2018/051528
Authority: WO
Inventors: Maksim Skorobogatiy; Hang QU; Xin Lu
Original assignee: Polyvalor, Limited Partnership
Priority date: 2017-12-08
Filing date: 2018-11-30
Publication date: 2019-06-13

Abstract

There is provided a lithium-ion battery in the form of a flexible wire comprising an anode and a cathode, wherein the anode and the cathode each comprise a conductive wire core, and wherein the cathode further comprises a coating comprising a cathode binder, LiFePO4, and a conductive carbon additive, wherein the anode and the cathode are each coated with an electrolyte comprising polyethylene oxide and a lithium salt; and wherein the anode and the cathode are woven together to form the flexible wire. A method of manufacturing said lithium-ion battery and uses of said lithium-ion battery are also provided.

Description

TITLE OF THE INVENTION

LITHIUM-ION BATTERY IN THE FORM OF A FLEXIBLE WIRE, PROCESS FOR MANUFACTURE AND USES THEREOF

CROSS REFERENCE TO RELATED APPLICATIONS

[001] This application claims benefit of provisional application Serial No. 62/596,314, filed on December 8, 2017.

FIELD OF THE INVENTION

[002] The invention relates to lithium-ion batteries that come in the form of a flexible (fiber) wire formed of a filiform anode and cathode twisted together. This invention further relates to a process for manufacturing said batteries.

BACKGROUND OF THE INVENTION

[003] Flexible, portable and wearable electronic devices are known, including on-garment displays, wearable sensors for sports and medicine, virtual-reality devices, smart phones, and smart watches and bracelets, which are commercially available and are utilized by a growing number of population. Most of these personal wearable electronics currently use conventional lithium-ion batteries (LIBs) as power sources. These LIBs are heavy and rigid, and thus not truly compatible with wearable applications.

[004] Attempts have been made to fabricate wire- (fiber-) shaped LIBs. Fiber LIBs have been fabricated by sequential deposition of battery-component thin-layers (such as in sequence of anode, electrolyte, cathode layer) on a conductive fiber substrate. Multiple fibers have also been embedded into an adhesive matrix to constitute a battery ribbon. Note that the fabrication of these fiber batteries requires complicated material deposition techniques such as magnetron sputtering and electron-beam evaporation which are inevitably operated in a high vacuum environment.

[005] There also exists fiber LIBs that can be fabricated using intrinsically conducting polymers by first electropolymerizing polypyrrole-hexafluorophosphate (PPy/PFe) on a platinum (Pt) wire as the cathode. The cathode wire is then inserted into a hollow-core polyvinylidene fluoride (PVDF) membrane separator winded by a polypyrrole-polystyrenesulfonate (PPy-PSS)-coated Pt wire as the anode. Finally, the whole structure is immersed in a glass vial filled with an electrolyte of lithium hexafluorophosphate (LiPFe) solution. This battery had a capacity of ~ 10 mAh/g. Replacing the PPy-PPS by single-walled carbon nanotubes (CNTs) for the fabrication of the anode improved the capacities to ~ 20 mAh/g. Both of these fiber batteries need to be immersed in liquid electrolytes to function, which makes them unsuitable for wearable applications.

[006] There also exists cable-type flexible LIBs that consist of a hollow spiral, spring like anode (comprising nickel-tin coated copper wires), a lithium cobalt oxide (UC0O2) cathode, and a polyethylene terephthalate) (PET) nonwoven separator membrane. After encapsulating the electrode wires into a heat-shrinking tube, 1 M LiPFe solution is injected into the battery as an electrolyte. This cable-type battery has a linear capacity of ~ 1 mAh/cm. Flexible, stretchable LIBs that are fabricated by parallel winding the anode wire and cathode wire into a spring like structure around an elastic fiber substrate are also known. Such anode and cathode wires are fabricated from CNT/lithium titanium oxide (LTO) composite and CNT/lithium manganate (LMO) composite, respectively. A gel electrolyte comprising lithium bis(trifluoromethane)sulfonamide ( LiTFS I )/polymer composite is coated onto the two electrode wires, and this gel electrolyte also functions as a battery separator. There also exists fiber-shaped aqueous LIBs that use a polyimide/CNT fiber as the anode and a LMO/CNT fiber as the cathode. The anode and cathode fibers are encapsulated into a heat-shrinkable tube and then an aqueous U₂SO₄ solution is injected into the tube as the electrolyte. While the use of an aqueous electrolyte solution could avoid safety issues caused by flammable organic electrolytes, the liquid electrolyte may leak out of the battery, thus leading to pollution and degradation of the battery performance.

[007] Further, there exists flexible batteries in the form of a thin band or even a film comprising cathode, anode, and electrolytic materials deposited as thin layers. These thin layers are deposited on a substrate of carbon paper coated with a thin metal layer. Such batteries are therefore in the form of a film/thin band. In many of these thin band batteries, a porous polyethylene membrane soaked with an electrolyte solution of LiPF6 is placed between the anode and cathode layer to function as a separator layer.

[008] Certain technical challenges are present in existing wire (fiber)-shaped LIBs. First, the majority of wire shaped LIBs utilize CNT fibers (yarns) for the electrode fabrication. The production of CNT fibers is extremely expensive, and often requires using expensive high-vacuum deposition instruments. Second, batteries using liquid organic electrolytes require careful handling during their operation, since leakage of the electrolyte could cause pollution and pose severe health risk to the users.

SUMMARY OF THE INVENTION

[009] In accordance with the present invention, there is provided: a lithium-ion battery in the form of a flexible wire comprising: an anode and a cathode, wherein the anode and the cathode each comprise a conductive wire core, and wherein the cathode further comprises a coating comprising a cathode binder, LiFePC , and a conductive carbon additive, wherein the anode and the cathode are each coated with an electrolyte comprising polyethylene oxide and a lithium salt; and wherein the anode and the cathode are woven together to form the flexible wire.

[0010] In accordance to another aspect of the present invention, there is provided A lithium-ion battery in the form of a flexible wire comprising: at least one anode and at least one cathode, wherein each anode and each cathode are independently the anode and the cathode as defined above, wherein each anode and each cathode are coated with an electrolyte, wherein each electrolyte is independently the electrolyte as defined above; and wherein the at least one anode and the at least one cathode are woven together to form the flexible wire.

[0011] According to another aspect of the present invention, there is provided a method of manufacturing a lithium-ion battery in the form of a flexible wire, the method comprising the step of weaving an anode and a cathode together to form the lithium-ion battery in the form of the flexible wire.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In the appended drawings: Figure 1 (a) shows a cross section of a LIB cathode wire; Figure 1 (b) shows a cross section of a LIB anode wire; Figure 1 (c) shows an anode wire and a cathode wire that were woven together using a home-made jig fabricated by a 3D printer. The inset shows a zoomed view of said woven-together wires.

Figure 2 shows the electrochemical performance of a battery using a LTO-PVDF composite-coated steel-filled polyester conductive thread (SPOT) anode. Figure 2(a) shows cell voltages and currents in the first 25 cyclic charge-discharge tests with different C-rates. Figure 2(b) shows a zoomed-in view of the cell voltage and current in the charge-discharge test with a 2-C rate. Figure 2(c) shows voltages of the battery in different charge- discharge cycles as a function of the battery capacity. Figure 2(d) shows specific capacity and coulombic efficiency of the battery measured in 50 charge-discharge cycles with different C rates.

Fig. 3 (a) shows an electrical impedance spectroscopy (EIS) spectrum of the battery using the LTO-PVDF composite-coated SPOT anode (the inset is the equivalent electric circuit of the battery). Figure 3(b) shows experimental capacity and coulombic efficiency of the battery during the bending tests. Figures 3(c) and 3(d) show experimental platform of the bending tests. Figures 3(e) shows a decorative sphere that has two batteries immobilized on it to light up an LED.

Figure 4 shows the electrochemical performance of a battery using a tin-coated SPOT anode. Figure 4(a) shows cell voltages and currents in the first 25 cyclic charge-discharge tests with different C-rates. Figure 4(b) shows a zoomed view of the cell voltage and current in the charge-discharge test with a 2-C rate. Figure 4(c) shows voltages of the battery in different charge-discharge cycles as a function of the battery capacity. Figure 4(d) shows specific capacity and coulombic efficiency of the battery measured in 50 charge-discharge cycles with different C rates.

Figure 5(a) shows an EIS spectrum of the battery using the tin-coated SPCT anode (the inset is the equivalent electric circuit of the battery). Figure 5(b) shows experimental capacity and coulombic efficiency of the battery during the bending tests.

Figure 6 shows electrochemical performance of a battery using a bare tin wire anode. Figure 6(a) shows cell voltages and currents in the first 25 cyclic charge-discharge tests with different C-rates. Figure 6(b) shows a zoomed view of the cell voltage and current in the charge-discharge test with a 2-C rate. Figure 4(c) shows voltages of the battery in different charge-discharge cycles as a function of the battery capacity. Figure 4(d) shows the specific capacity and coulombic efficiency of the battery measured in 50 charge-discharge cycles with different C rates.

Figure 7(a) shows an EIS spectrum of the battery using the bare tin wire anode (the inset is the equivalent electric circuit of the battery). Figure 7(b) shows the experimental capacity and coulombic efficiency of the battery during the bending tests.

DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention relates to a lithium-ion battery in the form of a flexible wire, together with its method of manufacture and uses, notably in fabrics and devices where battery space is limited.

Lithium-ion battery in the form of a flexible wire [0014] Turning now to the invention in more details, there is provided a lithium-ion battery in the form of a flexible wire comprising:

an anode and a cathode, wherein the anode and the cathode each comprise a conductive wire core, and wherein the cathode further comprises a coating comprising a cathode binder, LiFePC , and a conductive carbon additive,

wherein the anode and the cathode are each coated with an electrolyte comprising polyethylene oxide and a lithium salt; and

wherein the anode and the cathode are woven together to form the flexible wire.

[0015] The lithium-ion battery (LIB) is a rechargeable battery in which lithium ions move from the anode to the positive cathode during discharge and back when charging.

[0016] The LIB of the present invention is in the form of a flexible wire. The flexibility and shape of the LIB of the present invention allow it to be weaved into textiles or fabrics for wearable applications, or alternatively, coiled into compact power source units.

[0017] The anode of the LIB is an electrode where oxidation takes place in the battery. The anode of the present invention comprises a conductive wire core. The conductive wire core functions as a current collector for the anode. Accordingly, the thicker the conductive wire core of the anode, the more current it can carry. However, if the conductive wire core of the anode is too thick, it might be too inflexible, heavy, and/or unwieldy to be used in a flexible wire. In embodiments of the present invention, the thickness of the conductive wire core of the anode is at least about 100 mhh, about 150mhi, or about 200 mhi and/or at most about 350 mth, about 250 mhh, or about 200 mth. In embodiments of the present invention, the thickness of the conductive wire core of the anode is between about 100 mhi and about 350 mth, preferably between about 150 mhi and about 250 mth, and most preferably about 200 mhh.

[0018] In addition, the conductive wire core should be of sufficient flexibility such that, once woven together with the cathode, the resulting flexible wire is sufficiently flexible for any intended applications.

[0019] Naturally, the conductive wire core of the anode should be made of a conductive wire material. In embodiments of the invention, said conductive wire core can be any commercially available conductive wire, such as a conductive steel polymer wire, for example a steel-filled polyester conductive thread, or a conductive wire, preferably a conductive wire made of aluminum or tin. In preferred embodiments of the present invention, the conductive wire core is a conductive steel polymer wire, preferably a steel-filled polyester conductive thread, or a bare tin wire.

[0020] The anode may further comprise a coating. Said coating functions as the anode material for the LIB, meaning it is where oxidation takes place in the battery. The coating on the anode can be any anode coating known in the art that can function effectively at the thicknesses required, while still remaining sufficiently flexible. In preferred embodiments of the present invention, the coating on the anode is a tin coating, or the coating comprises an anode binder, LuTisO^ (LTO), and a conductive carbon additive. [0021] The anode binder can be any known anode binder in the art that is sufficiently flexible. In preferred embodiments of the present invention, the anode binder is polyethylene oxide or PVDF, preferably PVDF. In embodiments of the present invention, the weight percent of the binder with respect to the rest of the coating is at least about 20%, about 25%, or about 32% and/or at most about 40%, about 35%, or about 32%. In embodiments of the present invention, the weight percent of the binder with respect to the rest of the coating is between about 20% and about 40%, preferably between about 25% and about 35%, and most preferably about 32%.

[0022] The LTO functions as the anode material. In embodiments of the present invention, the weight percent of the LTO with respect to the rest of the coating is at least about 55%, about 60%, or about 64% and/or at most about 80%, about 70%, or about 64%. In embodiments of the present invention, the weight percent of the LTO with respect to the rest of the coating is between about 55% and about 80%, preferably between about 60% and about 70%, and most preferably about 64%.

[0023] The conductive carbon additive can be any conductive carbon additive known in the art that is sufficiently flexible at the thicknesses required. In preferred embodiments of the present invention, the conductive carbon additive is carbon nanofibers, carbon black, carbon nanotubes, or a mixture thereof. In preferred embodiments of the present invention, the conductive carbon additive is carbon nanofibers. In embodiments of the present invention, the weight percent of the conductive carbon additive with respect to the rest of the coating is at least about 2%, about 3%, or about 4% and/or at most about 10%, about 6%, or about 4%. In embodiments of the present invention, the weight percent of the conductive carbon additive with respect to the rest of the coating is between about 2% and about 10%, preferably between about 3% and about 6%, and most preferably about 4%.

[0024] It should be mentioned that, in the absence of the coating, the conductive wire core of the anode functions as the anode material. Accordingly, in the absence of said coating, the conductive wire core should be made of a material that can function as both an anode material and a current collector. In preferred embodiments of the present invention, the conductive wire core is a bare tin wire when no coating is present.

[0025] As with the thickness of the conductive wire core, the thickness of the coating on the anode will affect the weight, flexibility, size, and functionality of the anode. Specifically, an increased thickness will increase the amount of anodic material, but it might result in an anode that is too inflexible, heavy, and/or unwieldy to be used in a flexible wire. In embodiments of the present invention, the thickness of the coating on the anode is at least about 3mhh, about 5mhi, or about 10 mhi and/or at most about 25mhi, about 15mhh, or about 10 mhh. In embodiments of the present invention, the thickness of the coating on the anode is between about 3 mhi and about 25 mhh, preferably between about 5 mhi and about 15 mhh, and most preferably about 10 mth.

[0026] The respective thicknesses of the conductive wire core of the anode and the coating on the anode (if present) will determine the thickness of the anode. In embodiments of the present invention, the thickness of the anode is at least about 100mhi, about 150mhi, or about 210 mhi and/or at most about 370mhi, about 270mhi, or about 210 mhi. In embodiments of the present invention, the thickness of the anode is between about 100 mhi and about 370 mth, preferably between about 150 mhi and about 270 mhh, and most preferably about 210 mhh. [0027] The coating on the anode can be applied to the conductive wire core using any method known in the art. In preferred embodiments of the present invention, the coating on the anode is applied using a dip-and-dry technique.

[0028] In LIBs, the cathode is a positive lithium-based electrode, and lithium ions move from the negative electrode to the positive electrode during discharge and back when charging. The cathode of the present invention, like the anode, comprises a conductive wire core. The conductive wire core of the cathode functions as a current collector for the cathode. Accordingly, much like with the anode, the thicker the conductive wire core of the cathode, the more current it can carry. However, if the conductive wire core of the cathode is too thick, it might be too inflexible, heavy, and/or unwieldy to be used in a flexible wire. In embodiments of the present invention, the thickness of the conductive wire core of the cathode is at least about 100mhi, about 150mhi, or about 200 mhi and/or at most about 350mhi, about 250mhi, or about 200 mth. In embodiments of the present invention, the thickness of the conductive wire core of the cathode is between about 100 mhi and about 350 mth, preferably between about 150 mhi and about 250 mth, and most preferably about 200 mhh.

[0029] In addition, the conductive wire core should be of sufficient flexibility such that, once woven together with the anode, the resulting flexible wire is sufficiently flexible for any intended applications.

[0030] As with the conductive wire core of the anode, the conductive wire core of the cathode should be made of a conductive wire material. In embodiments of the invention, said conductive wire core can be any commercially available conductive wire, such as a conductive steel polymer wire, for example a steel-filled polyester conductive thread, or a conductive wire, preferably a conductive wire made of aluminum or tin. In preferred embodiments of the present invention, the conductive wire core of the cathode is a conductive steel polymer wire, preferably a steel-filled polyester conductive thread.

[0031] The respective conductive wire cores of the anode and the cathode can be made of the same material and/or have the same thickness, or they can each be made of different material and/or be of differing thickness.

[0032] The cathode further comprises a coating comprising a cathode binder, LiFePCU (LFP), and a conductive carbon additive. Said coating functions as the cathode material of the LIB of the present invention.

[0033] The cathode binder can be any known cathode binder in the art that is sufficiently flexible. In preferred embodiments of the present invention, the cathode binder is polyethylene oxide or PVDF, preferably PVDF. In embodiments of the present invention, the weight percent of the binder with respect to the rest of the coating is at least about 20%, about 25%, or about 32% and/or at most about 40%, about 35%, or about 32%. In embodiments of the present invention, the weight percent of the binder with respect to the rest of the coating is between about 20% and about 40%, preferably between about 25% and about 35%, and most preferably about 32%.

[0034] The LFP functions as the cathode material. In embodiments of the present invention, the weight percent of the LFP with respect to the rest of the coating is at least about 55%, about 60%, or about 64% and/or at most about 80%, about 70%, or about 64%. In embodiments of the present invention, the weight percent of the LFP with respect to the rest of the coating is between about 55% and about 80%, preferably between about 60% and about 70%, and most preferably about 64%.

[0035] The conductive carbon additive can be any conductive carbon additive known in the art that is sufficiently flexible at the thicknesses required. In embodiments of the present invention, the conductive carbon additive is carbon nanofibers, carbon black, carbon nanotubes, or a mixture thereof. In preferred embodiments of the present invention, the conductive carbon additive is carbon nanofibers. In embodiments of the present invention, the weight percent of the conductive carbon additive with respect to the rest of the coating is at least about 2%, about 3% or about 4% and/or at most about 10%, about 6%, or about 4%. In embodiments of the present invention, the weight percent of the conductive carbon additive with respect to the rest of the coating is between about 2% and about 10%, preferably between about 3% and about 6%, and most preferably about 4%.

[0036] As with the thickness of the conductive wire core, the thickness of the coating on the cathode will affect the weight, flexibility, size, and functionality of the cathode. Specifically, an increased thickness will increase the amount of cathode material, but it might result in a cathode that is too inflexible, heavy, and/or unwieldy to be used in a flexible wire. In embodiments of the present invention, the thickness of the coating on the cathode is at least about 3mhi, about 5mhi, or about 10 mhi and/or at most about 20mhi, about 15mhh, or about 10 mth. In embodiments of the present invention, the thickness of the coating on the cathode is between about 3 mhi and about 20 mhh, preferably between about 5 mhi and about 15 mhh, and most preferably about 10 mhi.

[0037] The respective thicknesses of the conductive wire core of the cathode and the coating on the cathode will determine the overall thickness of the cathode. In embodiments of the present invention, the thickness of the cathode is at least about 100mhi, about 150mhi, or about 210 mhi and/or at most about 370mhi, about 270mhi, or about 210 mhi. In embodiments of the present invention, the thickness of the cathode is between about 100 mhi and about 370 mth, preferably between about 150 mhi and about 270 mth, and most preferably about 210 mth.

[0038] The coating on the cathode can be applied to the conductive wire core using any method known in the art. In preferred embodiments of the present invention, the coating on the cathode is applied using a dip-and-dry technique.

[0039] The anode and the cathode are each coated with an electrolyte comprising polyethylene oxide and a lithium salt. The electrolyte allows for ionic movement between the anode and the cathode.

[0040] The electrolyte of the present invention comprises polyethylene oxide (PEO) and a lithium salt. The resulting electrolyte is solid, which avoids issues that arise from using a liquid electrolyte (such as leakage), while still remaining effective and sufficiently flexible.

[0041] The PEO serves as a polymer host for the lithium salt. The weight ratio of the PEO and the lithium salt in the electrolyte will affect the electrolyte’s effectiveness and flexibility. Accordingly, in embodiments of the present invention, weight ratio of the PEO and the lithium salt is at least about 1 :7, about 1 :6, or about 1 :5 and/or at most about 1 :3, about 1 :4, or about 1 :5. In embodiments of the present invention, the weight ratio of the PEO and the lithium salt is between about 1 :3 and about 1 :7, preferably between about 1 :4 and about 1 :6, and most preferably about 1 :5. It is to be understood that the above ratios reference the weights of the PEO and the lithium salt only, and do not take into consideration any additives or fillers.

[0042] The lithium salt can be any lithium salt known in the art for solid electrolytes. In embodiments of the invention, the lithium salt is LiPF₆, Lil, UCF₃SO₃, UCIO₄, or a mixture thereof. In preferred embodiments of the present invention, the lithium salt is LiPF₆.

[0043] The electrolyte may further comprise a filler. The filler could improve the electrolyte’s ionic conductivity by lowering the polymer crystallinity of the PEO. The filler can be any known filler in the art that would not adversely affect the functionality or flexibility of the electrolyte. In preferred embodiments of the invention, the filler is T1O_2, MgO, ZnO, AI₂O₃, or S1O₂, more preferably T1O₂.

[0044] [0042] In embodiments of the present invention the weight percent of the filler with respect to the rest of the electrolyte is at least about 3%, about 6%, or about 9% and/or at most about 14%, about 12%, or about 9%. In embodiments of the present invention, the weight percent of the filler with respect to the rest of the electrolyte is between about 3% and about 14%, preferably between about 6% and about 12%, and most preferably about 9%.

[0045] As the electrolyte is coating each of the anode and the cathode, it will add to their thickness. Having a layer that is too thick could negatively impact the weight, size, and flexibility of the resulting flexible wire. Accordingly, in embodiments of the present invention, the thickness of the electrolyte layer is at least about 20mhi, about 30mhi, or about 40 mhi and/or at most about 120mhi, about 80mhi, about 40 mhh. In embodiments of the present invention, the thickness of the electrolyte layer is between about 20 mhi and about 120 mth, preferably between about 30 mhi and about 80 mhh, and most preferably about 40 mth.

[0046] The electrolyte can be made and applied to the anode and cathode using any method known in the art. In preferred embodiments of the present invention, the electrolyte is applied using a dip-and-dry technique.

[0047] The anode and cathode can each have an electrolyte layer of differing thickness and/or composition, or the thickness and/or composition can be the same. The thickness of the electrolyte can also vary along the anode and/or the cathode.

[0048] The anode and the cathode are woven together to form the flexible wire. This means that the anode and cathode, which are both flexible and wire-shaped, are woven together such that the electrolyte on each electrode are in sufficient contact with each other to allow for effective ionic movement between the anode and the cathode. This means that there must be enough contact between the surface area of the electrolyte of the anode and the electrolyte of the cathode. By weaving the electrodes together, this surface contact is increased. The anode and the cathode can be woven together by twisting the anode and cathode, for example as shown in Figure 1c. The anode can also be wrapped around the cathode, or vice-versa; the result should produce enough surface contact between the electrolytes, while retaining a wire shape that is sufficiently flexible. Weaving the anode and cathode together also helps secure the anode to the cathode. The manner in which the anode and cathode are woven together will naturally affect the overall thickness and shape of the LIB. [0049] The LIB can further comprise a contact liquid. The contact liquid is placed on the electrolyte layers of the woven-together anode and cathode. This can enhance the bonding of the electrolyte layers on the two electrodes. The contact liquid can be any known solvent of PEO that will not adversely affect the efficacy or flexibility of the LIB. In preferred embodiments of the present invention, the contact liquid is propylene carbonate, DMF, toluene, or a mixture thereof. In a more preferred embodiment of the present invention, the contact liquid is propylene carbonate.

[0050] The LIB may further comprise an outer covering. Said outer covering can insulate the woven-together anode and cathode, and provide abrasion resistance and environmental protection to the LIB. The outer covering can completely or partially cover the LIB. The outer covering can be any known wire covering in the art that will not adversely affect the efficacy or the flexibility of the LIB. In embodiments of the present invention, the outer covering is a shrunk heat-shrinkable tube or electrical tape, preferably a shrunk heat-shrinkable tube. In embodiments of the present invention, the outer covering is at least one heat or UV curable resin.

[0051] The ends of the LIB, meaning the ends of the cathode and anode once woven together, can be sealed. This can help secure the materials of the LIB. It can also help secure the anode to the cathode and help prevent the weave from loosening or unraveling. In preferred embodiments of the present invention, the ends of the LIB can be sealed with epoxy.

[0052] The LIB is in the form of a flexible wire. The thickness, weight, and size of the flexible wire will depend on the thickness, shape, and size of the anode, cathode, electrolytes, and the outer covering (if present). In general, the thinner the wire, the more flexible it is. In embodiments of the present invention, the thickness of the LIB is at least about 0.7mm, about 0.9mm, or about 2 mm and/or at most about 4mm, about 2.5mm, or about 2 mm. In embodiments of the present invention, the thickness of the LIB is between about 0.7 mm and about 4 mm, preferably between about 0.9 mm and about 2.5 mm, and most preferably about 2 mm.

[0053] In another aspect of the present invention, there is provided a lithium-ion battery in the form of a flexible wire comprising:

at least one anode and at least one cathode,

wherein each anode and each cathode are coated with an electrolyte; and

wherein the at least one anode and the at least one cathode are woven together to form the flexible wire.

[0054] This LIB of the present invention is in the form of a flexible wire. The flexibility and shape of the LIB of this aspect of the present invention allow it to be weaved into textiles or fabrics for wearable applications, or alternatively, coiled into compact power source units.

[0055] In embodiments of the present invention, each anode, each cathode, and the electrolyte can independently be any one anode, cathode, or electrolyte defined above. It is to be understood that when multiple anodes and/or cathodes are used, each anode can be different or the same, each cathode can be different or the same, the electrolyte coating on each anode can be different or the same, and the electrolyte coating on each cathode can be different or the same. In embodiments of the present invention, the form of the flexible wire is also as defined above, taking into consideration that more than one anode and/or more than one cathode may be used. The thickness, weight, and size of the flexible wire will depend on the thickness, shape, and size of each anode, cathode, electrolyte, and the outer covering (if present). In general, the thinner the wire, the more flexible it is.

[0056] The at least one anode and the at least one cathode are woven together to form the flexible wire. This means that the at least one anode and the at least one cathode, which are each flexible and wire-shaped, are woven together such that the electrolyte on the at least one anode are in sufficient contact with the electrolyte on the at least one cathode to allow for effective ionic movement between the at least one anode and the at least one cathode. This means that there must be enough contact between the surface area of the electrolyte of the at least one anode and the electrolyte of the at least one cathode. By weaving the electrodes together, this surface contact is increased. When there is only one anode and one cathode, the at least one anode and the at least one cathode can be woven together as defined above. However, when there are multiple anodes and/or multiple cathodes, the at least one anode and the at least one cathode can be woven together like a braid, a weave, or any other configuration that will properly secure the at least one anode and the at least one cathode together while allowing for the appropriate amount of surface contact. The manner in which the at least one anode and the at least one cathode are woven together will naturally affect the overall thickness, shape, and flexibility of the resulting LIB.

Method of Manufacturing a Lithium-Ion Battery in the Form of a Flexible Wire

[0057] In another aspect, the present invention provides a method of manufacturing a lithium-ion battery in the form of a flexible wire, the method comprising the step of weaving an anode and a cathode together to form the lithium-ion battery in the form of the flexible wire.

[0058] In embodiments, the lithium-ion battery, the form of the flexible wire, the anode, and the cathode are as described in the previous section. It is understood that in the weaving step, there is an electrolyte on each of the anode and the cathode. In embodiments of the present invention, the electrolyte is as described in the previous section.

[0059] The step of weaving the anode and the cathode together comprises, as previously discussed, weaving the anode and cathode, which are both flexible and wire-shaped, together such that the electrolyte of each electrode are in sufficient contact with each other to allow for effective ionic movement between the anode and the cathode. This means that there must be enough surface contact between the electrolyte of the anode and the electrolyte of the cathode. By weaving the electrodes together, this surface contact is increased. Weaving the anode and cathode together also helps secure the anode to the cathode. The manner in which the anode and cathode are woven together will naturally affect the overall thickness and shape of the resulting LIB.

[0060] The step of weaving the anode and the cathode together can be performed using any known method that will not damage the LIB. In embodiments of the present invention, the anode and the cathode are twisted together, the anode is wrapped around the cathode, or the cathode is wrapped around the anode. In preferred embodiments of the present invention, the anode and the cathode are twisted together to produce a flexible wire, for example as shown in Figure 1 c. [0061] The step of weaving the anode and the cathode can be performed using any known instrument in the art. In embodiments of the invention, the anode and the cathode are woven together using a jig, or by hand, preferably by using a jig, most preferably by using the jig shown in Figure 1 c.

[0062] The method of the present invention may also comprise a step of coating the anode and/or the cathode with an electrolyte before the anode and the cathode are woven together. In embodiments of the present invention, the electrolyte is as described in the previous section. The anode and cathode can be coated with the electrolyte using any method known in the art. In preferred embodiments of the present invention, the electrolyte is applied using casting or a dip-and-dry technique, preferably a dip-and-dry technique.

[0063] The method of the present invention may also comprise a step of fabricating the anode and/or the cathode before the anode and/or the cathode are coated with the electrolyte. The fabricating of the anode comprises covering a conductive wire core with a coating, and the step of fabricating the cathode comprises coating a conductive wire core with a coating. In embodiments of the present invention, the coating for the anode and the cathode are as described in the previous section. The step of coating the conductive wire core with a coating can be performed using any known method in the art for coating a conductive material with an anode or cathode material. In preferred embodiments of the present invention, the coating is performed using physical vapor deposition, or a dip-and-dry technique, preferably a dip-and-dry technique.

[0064] The method of the present invention may also comprise a step of adding a contact liquid to the anode and cathode after the weaving step. In embodiments of the present invention, the contact liquid is as described in the previous section. In preferred embodiments of the present invention, the adding of the contact liquid is performed by wetting the electrolytes with a few drops of the contact liquid.

[0065] The method of the present invention may also comprise a step of encapsulating the LIB with an outer covering after the weaving step. In embodiments of the present invention, the outer covering is as described in the previous section. In preferred embodiments of the present invention, the outer covering is added by encapsulating, partially or completely, the LIB with a heat-shrinkable tube, and heating the heat-shrinkable tube at a sufficient temperature and for a sufficient amount of time such that the heat-shrinkable tube shrinks around the LIB. In a more preferred embodiment of the present invention, the heat-shrinkable tube is heated at 120 Q for 60 seconds.

[0066] In embodiments of the present invention, the outer covering is added by coating the LIB partially or fully with at least one heat or UV curable resin. In preferred embodiments of the present invention, the coating is performed by dipping the LIB into a monomer and then curing it.

[0067] The outer covering can be any color and possess a wide range of mechanical properties.

[0068] In another aspect, there is provided the method defined above, wherein instead of a singular anode and cathode, there is at least one anode and at least one cathode. In this aspect of the present invention, when more than one anode and/or cathode are used, the step of weaving the at least one anode and the at least one cathode together can be performed by weaving the at least one anode and the at least one cathode together like a braid, a weave, or any other configuration that will properly secure the at least one anode and the at least one cathode together while allowing for the appropriate amount of surface contact without damaging the LIB.

Properties, Uses and Applications of the lithium-ion batery in the form of a flexible wire

[0069] As discussed, the lithium-ion battery of the present invention is in the form of a flexible wire.

[0070] Due to its shape and flexibility, an application is in wearable technology and textiles, and/or or compact power source units. Indeed, certain embodiments of the invention could be woven into fabric by a standard loom. By incorporating the LIB of the present invention into fabrics and textiles, various applications are possible, including wearable technology used to monitor a user’s health. Given that such devices are in close contact with the user, they can easily collect data, including data on a user’s health, such as heart rate, calories burned, steps walked, blood pressure, and time spent in exercising.

[0071] The LIB of the present invention can also be used in devices where the space available for the battery is limited, such as medical devices or cell phones, smart packaging (including RFID tags) and various sensors. The LIB of the present invention could thus be rolled up on itself in any arbitrary form to fill a variety of available spaces.

[0072] On curved surface objects, the LIB of the present invention can be installed to perfectly match the surface. This could be useful for structural deformation sensors that are used in aeronautics, among other applications.

[0073] In preferred embodiments of the present invention, the LIB is used in on-garment displays, wearable sensors for sports and medicine, virtual-reality devices, smart phones, and smart watches and bracelets.

Advantages of the Invention

[0074] In one or more embodiments, the present invention may present one or more of the following advantages.

[0075] Some advantages include light weight, ease of fabrication, good flexibility, high specific capacitance, high energy density, and good durability. The LIB of the present invention is not only in the form of a flexible wire (which presents a wide variety of applications, as described in the previous section), but it possesses strong electrical specifications, including excellent coulombic efficiency, as well as strong specific capacity, voltage, and durability.

[0076] For example, the following electrical specifications may be achieved:

• Coulombic efficiency: ~ 90%

• Specific capacity: ~ 84 mAh / g

• Voltage: 3.4 V

• Durability: stable over 75 charge-discharge cycles; resists even if folded repeatedly

[0077] In addition, the LIB of the present invention may be easy and inexpensive to produce because it can use commercial materials available at low cost and does not require specialized equipment. [0078] As a completely solid device, the LIB of the present invention avoids electrolyte leakage. This renders it safe with no risk of leakage of flammable or hazardous liquids (which is a very important problem with batteries, and even more so in wearables). Compared to currently existing wire-(or fiber-) shaped LIBs that utilize electrolytes based on liquid organic solutions, the proposed LIB is much more advantageous for wearable applications at least in part thanks to its all-solid structure.

[0079] In addition, the manufacturing of the LIB according to the present invention is simple and can be performed at low cost due to the materials and techniques that can be used, such as the dip-and-dry technique.

Definitions

[0080] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

[0081] The terms "comprising", "having", "including", and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to") unless otherwise noted.

[0082] Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All subsets of values within the ranges are also incorporated into the specification as if they were individually recited herein.

[0083] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

[0084] The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed.

[0085] No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0086] Herein, the term "about" has its ordinary meaning. In embodiments, it may mean plus or minus 10% or plus or minus 5% of the numerical value qualified.

[0087] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0088] Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the accompanying drawings.

Description of Illustrative Embodiments

[0089] The present invention is illustrated in further details by the following non-limiting examples.

Overview [0090] Flexible wire-shaped LIBs were fabricated by twisting a cathode wire and an anode wire together using a 3-D printed jig. The cathode wire was fabricated by depositing a LiFePC -PVDF composite layer onto a steel-filled polyester conductive thread (SPOT) using a dip-and-dry method. As for the anode wire, a tin-coated SPOT, a LTO-PVDF composite-coated SPOT, and a bare tin wire were used. Furthermore, an all-solid UPF₆- polyethylene oxide (PEO) composite layer that functions as both the electrolyte and battery separator was deposited onto cathode and anode wires before the battery assembly. Titanium oxide (T1O2) nanoparticles were doped into the electrolyte layer in order to lower the polymer crystallinity and increase the ionic conductivity. The electrochemical performance of the proposed wire LIBs was characterized via standard C-rate charge-discharge tests. Experimental results suggest that the LIBs using the LTO-PVDF composite-coated SPOT anode, the tin- coated SPOT anode and the bare tin wire anode could achieve a specific capacity of—64,—67, and ~96 mAh/g, respectively, when charge-discharged at 0.5-C rate. The battery could effectively retain its capacity after intensive charge-discharge cycles. During battery operation, the coulombic efficiency of the battery remained above -80%. The fabricated batteries also went through a series of bending tests in which the repeated bend- release motions of the batteries were implemented, while the batteries were cyclically charge-discharged at 1 C rate. Experimentally, the batteries effectively maintained their electrochemical properties after -30000 bend- release cycles. It should be noted that the fabrication of the LIB followed a very simple route, and the battery component materials were all cost-effective and commercially available. In addition, the fabricated LIBs featured an all-solid structure, thus avoiding electrolyte leakage, as well as any corresponding safety issues that occur with batteries based on liquid electrolyte. Other advantages of the fabricated LIBs include light weight, ease of fabrication, good flexibility, high specific capacitance, high energy density, and good durability.

Fabrication and characterization of wire-shaped L/Bs

(1 ) LIBs comprising a LFP-PVDF composite-coated SPOT cathode and a LTO-PVDF composite-coated SPOT anode

[0091] LIBs were fabricated using a LFP-PVDF composite-coated SPOT cathode and a LTO-PVDF composite-coated SPOT anode. To fabricate the LIB cathode wire, a LFP-PVDF composite solution was first prepared by dissolving a defined amount of LFP and PVDF into 1 -Methyl-2-pyrrolidinone (NMP) solvent. A defined amount of carbon-nanofiber powders was also added into the cathode solution to increase the conductivity. Then, the LFP composite layer was deposited onto a SPOT using the dip-and-dry method. A cross section of the resulting cathode is shown in Fig. 1 (a). Similarly, to fabricate the LTO-PVDF composite-coated SPOT anode, a LTO-PVDF solution was first prepared by dissolving a defined amount of LTO, PVDF, and carbon nanofiber powders into NMP solvent. Then, a LTO composite layer was deposited onto a SPOT also using the dip-and-dry method. Before the battery was assembled, a UPF₆-PEO composite electrolyte layer that also functions as the battery separator was coated on the anode and cathode wires, respectively, via a dip-and- dry process. A cross section of the resulting anode is shown in Fig. 1 (b). The electrolyte solution was prepared by dissolving a defined amount of UPF₆ and PEO into acetonitrile solvent. T1O2 was also added into the electrolyte solution in order to lower the polymer crystallinity and improve the electrolyte ionic conductivity. [0092] As shown in Fig. 1 (c), the two electrode wires were twisted using a home-made jig fabricated using a Makerbot 3D printer. In order to enhance the bonding of the electrolyte layers on the two electrode wires, the battery was then wetted with several drops of propylene carbonate. Finally, the battery was encapsulated with a heat-shrinkable tube, and was heated at 120 Q for 60 seconds. Note that the dip-and-dry process, as well as the battery assembly process, was all carried out inside the N2-filled glove box.

[0093] The electrochemical properties of a full wire-shaped LIB using the LTO-PVDF composite-coated SPOT anode were investigated using a cyclic charge-discharge analysis with different charge-discharge rates (from 0.5 C to 8 C) as shown in Fig. 2 (a, b). Experimentally, charge-discharge tests on a ~12 cm-long battery stored inside the N2-filled glove box were carried out using an Ivium Electrochemical Workstation. The open- circuit voltage of both samples was found to be ~ 2.1 V. As shown in Fig. 2(c, d), the battery had specific capacities of 64.1 , 33.7, 17.7, 8.5, 3.8 mAh/g at 0.5, 1 , 2, 4, and 8 C, respectively. It can be seen that the charge- discharge capacities exhibit a tendency to decrease with the increment of current density; however, the voltage plateau remained clearly flat even when the current density was up to 8 C, indicating an excellent charge- discharge performance. After a series of tests with different C rates, the capacity of the LIB was ~ 29.3 mAh/g, when the rate turned back to 1 C. This indicates that the structure of each component of the full battery remained intact after being subjected to high current densities. Finally, 25 cycles of charge-discharge tests at 1 C rate were performed, and it was found that the battery could still retain 82% of its original capacity after these cyclic charge-discharge tests. The coulombic efficiencies of the battery were greater than 83% during the whole charge-discharge cycles (Fig. 2(d)).

[0094] The EIS measurement of battery was also performed. The Nyquist plot of the battery (shown in Fig. 3(a)) is composed of a depressed semicircle in the high-to-medium frequency region followed with a slope in the low frequency region. According to the order of descending frequency, the EIS spectrum could be divided into three distinct regions. The first intercept on the real axis in Fig. 3(a) gives the equivalent series resistance, R_s, which is a bulk electrolyte resistance. The second intercept gives a sum of the electrolyte resistance, R_s and the charge transfer resistance, R_ct, which is the electrode-electrolyte interfacial resistance. From Fig. 3(a), R_s and R_ct of the battery are -208 W and -856 W, respectively.

[0095] A series of cyclic bend-release tests were also performed to verify the durability of the battery. Experimentally, the charge-discharge tests of the battery were performed at 1 C rate, while the battery was subject to repeated bend-release cycles. In a single bend-release cycle, while one end of the battery was fixed, the other end of the battery is displaced by 2 cm and then pulled back to its original position. The period of a single bend-release cycle is 4 s. Totally, more than 30000 bend-release cycles were carried out during 20 charge-discharge tests. The specific capacity of the battery was still over 86% of the original after these bend- release cycles, and the coulombic efficiency of the battery remain consistent 94% during all the charge-discharge tests.

[0096] Fig. 3(e) demonstrates that an LED (working voltage: 3.3 V, working current -20 mA) could be lit up by two batteries connected in series. Thanks to their flexibilities, the batteries could be easily immobilized in the V-grooves on the surface of a sphere fabricated via 3D printing. (2) L/Bs comprising a LFP-PVDF composite-coated SPOT cathode and a tin-coated SPOT anode

[0097] In this example, a tin-coated SPCT anode was fabricated, which is actually a SPCT coated with a thin tin layer using the PVD technique. To fabricate tin-coated SPCT anode, a PVD evaporator (Edwards Inc.) was used to deposit a ~1.6 micron thick tin layer on the surface of SPCTs. It should be noted that fabrication of the LFP-PVDF composite-coated SPCT cathode follows the same procedure mentioned in the previous section, and so does the preparation of the electrolyte solution. Finally, the two electrode wires were also coated with the electrolyte layers (defined in the previous section) via a dip-and-dry process and assembled into a battery.

[0098] The cyclic charge-discharge tests of this full wire-shaped LIB using the tin-coated SPCT anode and LFP-PVDF composite-coated SPCT cathode were performed with different charge-discharge rates (from 0.5 C to 8 C) as shown in Fig. 4. The open-circuit voltage of both samples was found to be - 3.2 V. As shown in Fig. 4(c, d), the battery had specific capacities of 67.1 , 47.3, 35, 20.4, 12.5 mAh/g at 0.5, 1 , 2, 4, and 8 C, respectively. 25 cycles of charge-discharge tests of the battery at 1 C rate were performed to verify the battery durability, and the specific capacity of the battery was still over 85% of the original. The coulombic efficiency of the battery maintained above 81 % for all of the cyclic charge-discharge tests. Moreover, note that the R_s and R_ct of the battery are -134 W and -276 W, respectively, according to the EIS spectrum as shown in Fig. 5(a).

[0099] The bending test of the battery was also performed using the same scenario as described in the previous section. -31000 bend-release actions were implemented during 20 cycles of charge-discharge tests. The experimental specific capacity and coulombic efficiency of the battery during the bending tests are shown in Fig. 5(b). While the capacity decreased by 14% after 20 cycles of charge-discharge tests, the coulombic efficiency of the battery maintained greater than 84% for all the cycles, while mostly staying above 90%.

(3) L/Bs comprising a LFP-PVDF composite-coated SPCT cathode and a tin wire anode

[00100] Finally, a wire-shaped battery comprising a LFP-PVDF composite-coated SPCT cathode and a tin wire anode was fabricated, and the performance of this battery was compared to its peer using the tin-coated SPCT anode (defined in the previous section). Fabrication of this battery followed the same procedures as those demonstrated in the previous section; however, the tin-coated SPCT anode was replaced by a bare tin wire with a diameter of 500

[00101] Cyclic charge-discharge tests of this battery at different C rates were performed, as shown in Fig. 6. The specific capacities of the battery were found to be 95.7, 72.3, 40, 19.4, 17.5 mAh/g at 0.5, 1 , 2, 4, and 8 C, respectively. After the total 50 cycles of charge-discharge tests with different C rates, the specific capacity of the battery decreased by 7.5%. The coulombic efficiency of the battery maintained above 83% for all of the cyclic charge-discharge tests. Moreover, the /?_y and R_ct o\ the battery are -97 W and -190 W, respectively, according to the EIS spectrum as shown in Fig. 7(a). Thus, the electrolyte resistance and the charge-transfer resistance of the battery using tin-coated SPCT anode are somewhat higher while still comparable to those of the battery using bare tin wire anode. Finally, the results of the bending test for the battery using a bare tin wire anode are also presented. The coulombic efficiency of the battery during the whole bending test is above 85% while mostly staying over 91 %, and the specific capacity of the battery dropped by 8% after 20 cycles of charge-discharge tests (at 1 C rate) in the bending tests (as shown in Fig. 7(b)). Conclusions

[00102] In summary, all-solid wire-shaped LIBs were fabricated and assembled by twisting a cathode wire with an anode wire. The cathode wire was fabricated by depositing a LFP composite layer on a SPCT via a dip-and- dry process. As for the anode wires, several examples were explored, including the LTO-composite coated SPCT (dip-and-dry deposition), tin-coated SPCT (PVD deposition) as well as a bare tin wire. The electrolyte composite layer consisting of LiPF6 and PEO was then deposited onto both the anode and cathode wire before the battery assembly. By twisting the cathode wire and anode wire together using a customized jig, the batteries were then assembled. The open-circuit voltage was found to be ~ 2.3 V for the battery using the LTO-PVDF composite-coated SPCT anode, and ~3.3 V for the battery using the tin-coated SPCT anode and the tin wire anode. Charge-discharge tests were carried out at different C rates for each battery sample. Experimental results suggest that the LIBs using the LTO-PVDF composite-coated SPCT anode, the tin-coated SPCT anode and the bare tin wire anode could achieve a specific capacity of—64,—67, and ~96 mAh/g, respectively, when discharged at 0.5-C rate. The battery could effectively retain its capacity after intensive charge-discharge cycles. During battery operation, the coulombic efficiency of the battery remained above 80%. The fabricated batteries, after undertaking massive bend-release motions, could still effectively retain their electrochemical performance. The fabrication of the proposed LIB was very simple and cost-effective, and the battery component materials were all commercially available. In addition, these LIBs featured an all-solid structure, thus avoiding the electrolyte leakage and the corresponding safety issues for batteries based on liquid electrolytes. Compared to currently existing wire- (fiber-) shaped LIBs that utilize electrolytes based on liquid organic solutions, the fabricated LIBs are much more advantageous for wearable applications thanks to its all-solid structure.

Experimental Section

(1) Fabrication of the electrode wires

[00103] To fabricate the LFP-PVDF composite-coated SPCT cathode wires, a polyvinylidene fluoride (PVDF) solution was first prepared by dispersing 1 g PVDF (powder, Mw. -534,000, Sigma-Aldrich) into 10 ml 1 -Methyl-2- pyrrolidinone (NMP) solvent (99.5%, Sigma-Aldrich) using a magnetic stirrer for 2 hours at room temperature (22 C). 0.425 g LFP (Phostech Lithium Inc.) was manually ground for 10 minutes and then mixed with 0.025 g carbon nanofibers (Sigma-Aldrich). The mixture was then dispersed into 2 ml as-prepared PVDF solution using the magnetic stirrer for 6 hours at room temperature (22 C). The SPCTs were rinsed by water and isopropanol for 15 minutes each in the ultrasonic bath. The cathode wires were fabricated by depositing a LFP composite layer onto the SPCTs via a dip-and-dry process in the i h-filled glove box.

[00104] Fabrication of LTO-PVDF composite-coated SPCT anode wires followed the procedure described above, except that the LFP was replaced by the same weight of LTO (Sud-Chemie Inc.).

[00105] The tin-coated SPCT anode wires were produced by depositing a -1.6 mhΊ-ίIi^ tin (99.9%, Sigma- Aldrich) layer on the SPCTs by PVD (evaporative deposition, Edwards High Vacuum Ltd.). The PVD was performed under a high vacuum condition (— 10^~7 mbar) with a deposition rate of 0.2 nm/s. Then, the tin-coated SPCT wires were stored in the i h-filled glove box for subsequent procedures. [00106] The bare tin wire anodes (diameter: 0.5 mm, 99%, Sigma-Aldrich) were rinsed with regular detergent, 2 wt% HCI solution, and isopropanol for 20 minutes each in an ultrasonic bath. After rinsing, the tin wires were blown to dry with N2 flow, and then were stored in a Infilled glove box.

(2) Preparation of the electrolyte solution, and deposition of electrolyte layer on the electrode wires

[00107] 0.125 g LiPFe (powder, Sigma-Aldrich) and 0.08 g T1O2 (nanopowder, Sigma-Aldrich) was dispersed into 12.5 ml acetonitrile (99.9%, Sigma-Aldrich) solvent for 3 hours using a magnetic stirrer at room temperature (22 C). Then, 0.665 g polyethylene oxide (powder, Mw -400,000, Sigma-Aldrich) was added into the solution which was then stirred for 12 hours. The as-prepared solution was casted onto both the cathode and anode wires to form an electrolyte layer which also functions as the battery separator. All these processes were carried out in the i b-filled glove box.

(3) Assembly of wire-shaped batteries

[00108] The cathode and anode wires were twisted into a battery using a home-made jig fabricated with a Makerbot 3D printer. The twisted LIB was then wetted by several drops of propylene carbonate. Finally, the LIBs were encapsulated with a heat-shrinkable tube and were heated at 120 Q for 60 seconds. Both ends of the LIB were then sealed with epoxy.

REFERENCES

[00109] The present description refers to a number of documents, the content of which is herein incorporated by reference in their entirety. These documents include, but are not limited to, the following:

• Bubnova, O., Wearable electronics: Stretching the limits. Nature Nanotechnoiogyl&Xl , 12{2), 101-101.

• Dias, T., Electronic Textiles: Smart Fabrics and Wearable Technology. Elsevier Science: 2015.

• Stoppa, M.; Chiolerio, A., Wearable electronics and smart textiles: a critical review. Sensors 2014, 14 (7), 1 1957-11992.

• Gwon, FI.; Hong, J.; Kim, FI.; Seo, D.-FL; Jeon, S.; Kang, K., Recent progress on flexible lithium rechargeable batteries. Energy & Environmental Science 2014, 7(2), 538-551.

• Zhou, G.; Li, F.; Cheng, H.-M., Progress in flexible lithium batteries and future prospects. Energy & Environmental Science 7&\ , 7(4), 1307-1338.

• Neudecker, B. J.; Benson, M. H.; Emerson, B. K. Power fibers: Thin-fiim batteries on fiber substrates, DTIC Document: 2003.

• Wang, J.; Too, C. O.; Wallace, G. G., A highly flexible polymer fibre battery. Journal of power sources

2005, 150, 223-228.

• Wang, J.; Wang, C.; Too, C.; Wallace, G., Highly-flexible fibre battery incorporating polypyrrole cathode and carbon nanotubes anode. Journal of power sources 2006, /67(2), 1458-1462. • Kwon, Y. H.; Woo, S. W.; Jung, H. R.; Yu, H. K.; Kim, K.; Oh, B. H.; Ahn, S.; Lee, S. Y.; Song, S. W.; Cho, J., Cable-type flexible lithium ion battery based on hollow multi-helix electrodes. Advanced Materials 2, 24 [38), 5192-5197.

• Ren, J.; Zhang, Y.; Bai, W.; Chen, X.; Zhang, Z.; Fang, X.; Weng, W.; Wang, Y.; Peng, H., Elastic and wearable wire-shaped lithium-ion battery with high electrochemical performance. Angewandte Chemie 2014, 126( 30), 7998-8003.

• Weng, W.; Sun, Q.; Zhang, Y.; Lin, H.; Ren, J.; Lu, X.; Wang, M.; Peng, H., Winding aligned carbon nanotube composite yarns into coaxial fiber full batteries with high performances. Nano letters 2014, 14 (6), 3432-3438.

• Lin, H.; Weng, W.; Ren, J.; Giu, L; Zhang, Z.; Chen, P.; Chen, X.; Deng, J.; Wang, Y.; Peng, H., Twisted Aligned Carbon Nanotube/Silicon Composite Fiber Anode for Flexible Wire-Shaped Lithium-Ion Battery. Advanced Materials ml·, 26(8), 1217-1222.

• Zhang, Y.; Bai, W.; Ren, J.; Weng, W.; Lin, H.; Zhang, Z.; Peng, H., Super-stretchy lithium-ion battery based on carbon nanotube fiber. Journal of Materials Chemistry A 2014, 2{29), 1 1054-1 1059.

• Liu, Y.-FL; Takasaki, T.; Nishimura, K.; Yanagida, M.; Sakai, T., Development of lithium ion battery using fiber-type lithium-rich cathode and carbon anode materials. Journal of Power Sources 2015, 290, 153- 158.

• Zhang, Y.; Wang, Y.; Wang, L.; Lo, C.-M.; Zhao, Y.; Jiao, Y.; Zheng, G.; Peng, H., A fiber-shaped aqueous lithium ion battery with high power density. Journal of Materials Chemistry A 2016, 4 (23), 9002-9008.

• Zhang, Y.; Bai, W.; Cheng, X.; Ren, J.; Weng, W.; Chen, P.; Fang, X.; Zhang, Z.; Peng, H., Flexible and stretchable lithium-ion batteries and supercapacitors based on electrically conducting carbon nanotube fiber springs. Angewandte Chemie International Edition , 53 ( 52), 14564-14568.

• Eskandarian, L., Development and Optimization of Solid Polymer Electrolyte for Lithium Ion Batteries.

Claims

1. A lithium-ion battery in the form of a flexible wire comprising:

wherein the anode and the cathode are woven together to form the flexible wire.

2. The lithium-ion battery of claim 1 , wherein a thickness of the conductive wire core of the anode is at least about 100 mhh, about 150mhi, or about 200 mhi and/or at most about 350 mhh, about 250 mhh, or about 200 mtti.

3. The lithium-ion battery of claim 1 , wherein a thickness of the conductive wire core of the anode is between about 100 mhi and about 350 mtti, preferably between about 150 mhi and about 250 mhh, and most preferably about 200 mhh.

4. The lithium-ion battery of any one of claims 1 to 3, wherein the conductive wire core of the anode is any commercially available conductive wire.

5. The lithium-ion battery of any one of claims 1 to 4, wherein the conductive wire core of the anode is a conductive steel polymer wire, or a conductive wire, preferably a conductive wire made of tin.

6. The lithium-ion battery of any one of claims 1 to 5, wherein the conductive wire core of the anode is a conductive steel polymer wire, preferably a steel-filled polyester conductive thread, or a bare tin wire.

7. The lithium-ion battery of any one of claims 1 to 6, wherein the anode further comprises a coating.

8. The lithium-ion battery of claim 7, wherein the coating on the anode is a tin coating, or the coating comprises an anode binder, LuTisO^ (LTO), and a conductive carbon additive.

9. The lithium-ion battery of claim 8, wherein the anode binder is polyethylene oxide or PVDF, preferably PVDF.

10. The lithium-ion battery of claim 9, wherein the anode binder PVDF.

11. The lithium-ion battery of any one of claims 8 to 10, wherein a weight percent of the anode binder with respect to the rest of the coating is at least about 20%, about 25%, or about 32% and/or at most about 40%, about 35%, or about 32%.

12. The lithium-ion battery of any one of claims 8 to 10, wherein a weight percent of the anode binder with respect to the rest of the coating is between about 20% and about 40%, preferably between about 25% and about 35%, and most preferably about 32%.

13. The lithium-ion battery of any one of claims 8 to 12, wherein a weight percent of the LTO with respect to the rest of the coating is at least about 55%, about 60%, or about 64% and/or at most about 80%, about 70%, or about 64%.

14. The lithium-ion battery of any one of claims 8 to 12, wherein the weight percent of the LTO with respect to the rest of the coating is between about 55% and about 80%, preferably between about 60% and about 70%, and most preferably about 64%.

15. The lithium-ion battery of any one of claims 8 to 14, wherein the conductive carbon additive is carbon nanofibers, carbon black, carbon nanotubes, or a mixture thereof.

16. The lithium-ion battery of claim 15, wherein the conductive carbon additive is carbon nanofibers.

17. The lithium-ion battery of any one of claims 8 to 16, wherein a weight percent of the conductive carbon additive with respect to the rest of the coating is at least about 2%, about 3%, or about 4% and/or at most about 10% or about 6%, or about 4%.

18. The lithium-ion battery of any one of claims 8 to 16, wherein the weight percent of the conductive carbon additive with respect to the rest of the coating is between about 2% and about 10%, preferably between about 3% and about 6%, and most preferably about 4%.

19. The lithium-ion battery of any one of claims 8 to 18, wherein a thickness of the coating on the anode is at least about 3mhi, about 5mhi, or about 10 mhi and/or at most about 25mhi, about 15mth, or about 10 mtti.

20. The lithium-ion battery of any one of claims 8 to 18, wherein the thickness of the coating on the anode is between about 3 mhi and about 25 mhi, preferably between about 5 mhi and about 15 mhi, and most preferably about 10 mhh.

21. The lithium-ion battery of any one of claims 8 to 20, wherein the coating on the anode has been applied using a dip-and-dry technique.

22. The lithium-ion battery of any one of claims 1 to 6, wherein the conductive wire core is a bare tin wire.

23. The lithium-ion battery of any one of claims 1 to 22, wherein a thickness of the anode is at least about 100mhi, about 150mhi, or about 210 mhi and/or at most about 370mhi, about 270mhi, or about 210 mhh.

24. The lithium-ion battery of any one of claims 1 to 22, wherein a thickness of the anode is between about 100 mhi and about 370 mhi, preferably between about 150 mhi and about 270 mhi, and most preferably about 210 mtti.

25. The lithium-ion battery of any one of claims 1 to 24, wherein a thickness of the conductive wire core of the cathode is at least about 100mhi, about 150mhi, or about 200 mhi and/or at most about 350mhi, about 250mhi, or about 200 mhh.

26. The lithium-ion battery of any one of claims 1 to 24, wherein the thickness of the conductive wire core of the cathode is between about 100 mhi and about 300 mhh, preferably between about 150 mhi and about 250 mhi, and most preferably about 200 mtti.

27. The lithium-ion battery of any one of claims 1 to 26, wherein the conductive wire core of the cathode is any commercially available conductive wire.

28. The lithium-ion battery of any one of claims 1 to 27, wherein the conductive wire core of the cathode is a conductive steel polymer wire, preferably a steel-filled polyester conductive thread, or a conductive wire, preferably a conductive wire made of tin.

29. The lithium-ion battery of any one of claims 1 to 28, wherein the conductive wire core of the cathode is a conductive steel polymer wire, preferably a steel-filled polyester conductive thread.

30. The lithium-ion battery of any one of claims 1 to 29, wherein the conductive wire cores of the anode and the cathode are made of the same material and/or have the same thickness.

31. The lithium-ion battery of any one of claims 1 to 29, wherein the conductive wire cores of the anode and the cathode are each made of different materials and/or are of differing thicknesses.

32. The lithium-ion battery of any one of claims 1 to 31 , wherein the cathode binder is polyethylene oxide or PVDF, preferably PVDF.

33. The lithium-ion battery of any one of claims 1 to 32, wherein the cathode binder is PVDF.

34. The lithium-ion battery of any one of claims 1 to 33, wherein a weight percent of the cathode binder with respect to the rest of the coating is at least about 20%, about 25%, or about 32% and/or at most about 40%, about 35%, or about 32%.

35. The lithium-ion battery of any one of claims 1 to 33, wherein a weight percent of the cathode binder with respect to the rest of the coating is between about 20% and about 40%, preferably between about 25% and about 35%, and most preferably about 32%.

36. The lithium-ion battery of any one of claims 1 to 35, wherein a weight percent of the LFP with respect to the rest of the coating is at least about 55%, about 60%, or about 64% and/or at most about 80%, about 70%, or about 64%.

37. The lithium-ion battery of any one of claims 1 to 35, wherein a weight percent of the LFP with respect to the rest of the coating is between about 55% and about 80%, preferably between about 60% and about 70%, and most preferably about 64%.

38. The lithium-ion battery of any one of claims 1 to 37, wherein the conductive carbon additive is carbon nanofibers, carbon black, carbon nanotubes, or a mixture thereof.

39. The lithium-ion battery of any one of claims 1 to 38, wherein the conductive carbon additive is carbon nanofibers.

40. The lithium-ion battery of any one of claims 1 to 39, wherein a weight percent of the conductive carbon additive with respect to the rest of the coating is at least about 2%, about 3% or about 4% and/or at most about 10%, about 6%, or about 4%.

41. The lithium-ion battery of any one of claims 1 to 39, wherein a weight percent of the conductive carbon additive with respect to the rest of the coating is between about 2% and about 10%, preferably between about 3% and about 6%, and most preferably about 4%.

42. The lithium-ion battery of any one of claims 1 to 41 , wherein a thickness of the coating on the cathode is at least about 3mhi, about 5mhi, or about 10 mhi and/or at most about 20mhi, about 15mhi, or about 10 mtti.

43. The lithium-ion battery of any one of claims 1 to 41 , wherein a thickness of the coating on the cathode is between about 3 mhi and about 20 mhi, preferably between about 5 mhi and about 15 mhi, and most preferably about 10 mtti.

44. The lithium-ion battery of any one of claims 1 to 43, wherein a thickness of the cathode is at least about 100mhi about 150mhi, or about 210 mhi and/or at most about 370mhi, about 270mhi, or about 210 mhh.

45. The lithium-ion battery of any one of claims 1 to 43, wherein a thickness of the cathode is between about 100 mhi and about 370 mhi, preferably between about 150 mhi and about 270 mhh, and most preferably about 210 mtti.

46. The lithium-ion battery of any one of claims 1 to 45, wherein the coating on the cathode has been applied using a dip-and-dry technique.

47. The lithium-ion battery of any one of claims 1 to 46, wherein a weight ratio of the PEO and the lithium salt is at least about 1 :7, about 1 :6, or about 1 :5 and/or at most about 1 :3, about 1 :4, or about 1 :5.

48. The lithium-ion battery of any one of claims 1 to 46, wherein a weight ratio of the PEO and the lithium salt is between about 1 :3 and about 1 :7, preferably between about 1 :4 and about 1 :6, and most preferably about 1 :5.

49. The lithium-ion battery of any one of claims 1 to 48, wherein the lithium salt is LiPF₆, Lil, UCF₃SO₃, UCIO₄, or a mixture thereof.

50. The lithium-ion battery of any one of claims 1 to 49, wherein the lithium salt is UPF₆.

51. The lithium-ion battery of any one of claims 1 to 50, wherein the electrolyte further comprises at least one filler.

52. The lithium-ion battery of claim 51 , wherein the filler is T1O2_, MgO, ZnO, AI₂O₃, or S1O2, preferably T1O2.

53. The lithium-ion battery of any one of claims 1 to 52, wherein a weight percent of the filler with respect to the rest of the electrolyte is at least about 3%, about 6%, or about 9% and/or at most about 14%, about 12%, or about 9%.

54. The lithium-ion battery of any one of claims 1 to 52, wherein a weight percent of the filler with respect to the rest of the electrolyte is between about 3% and about 14%, preferably between about 6% and about 12%, and most preferably about 9%.

55 The lithium-ion battery of any one of claims 1 to 54, wherein a thickness of the electrolyte layer is at least about 20mhi, about 30mhi, or about 40 mhi and/or at most about 120mhi, about 80mhi, about 40 mhh.

56. The lithium-ion battery of any one of claims 1 to 54, wherein a thickness of the electrolyte layer is between about 20 mhi and about 120 mhi, preferably between about 30 mhi and about 80 mhi, and most preferably about 40 mhi.

57. The lithium-ion battery of any one of claims 1 to 56, wherein the electrolyte has been applied to the anode and/or the cathode using a dip-and-dry technique.

58. The lithium-ion battery of any one of claims 1 to 57, wherein the anode and cathode each have an electrolyte layer of differing thickness and/or composition.

59. The lithium-ion battery of any one of claims 1 to 57, wherein the thickness and/or composition of the electrolyte on the anode and the cathode is the same.

60. The lithium-ion battery of any one of claims 1 to 59, wherein the thickness of the electrolyte varies along the anode and/or the cathode.

61. The lithium-ion battery of any one of claims 1 to 60, wherein the anode and the cathode have been woven together by twisting the anode and cathode, by wrapping the anode around the cathode, or by wrapping the cathode around the anode.

62. The lithium-ion battery of any one of claims 1 to 61 , wherein the anode and the cathode have been woven together by twisting the anode and cathode.

63. The lithium-ion battery of any one of claims 1 to 62, wherein the lithium-ion battery further comprises a contact liquid.

64. The lithium-ion battery of claim 63, wherein the contact liquid is propylene carbonate, DMF, toluene, or a mixture thereof.

65. The lithium-ion battery of claim 64, wherein the contact liquid is propylene carbonate.

66. The lithium-ion battery of any one of claims 1 to 65, wherein the lithium-ion battery further comprises an outer covering.

67. The lithium-ion battery of claim 66, wherein the outer covering is a shrunk heat-shrinkable tube or electrical tape, preferably a shrunk heat-shrinkable tube.

68. The lithium-ion battery of claim 66, wherein the outer covering is at least one heat or UV curable resin.

69. The lithium-ion battery of any one of claims 1 to 68, wherein ends of the LIB are sealed.

70. The lithium-ion battery of claim 69, wherein the ends of the LIB are sealed with epoxy.

71. The lithium-ion battery of any one of claims 1 to 70, wherein a thickness of the LIB is at least about

0.7mm, about 0.9mm, or about 2 mm and/or at most about 4mm, about 2.5mm, or about 2 mm.

72. The lithium-ion battery of any one of claims 1 to 70, wherein the thickness of the lithium-ion battery is between about 0.7 mm and about 4 mm, preferably between about 0.9 mm and about 2.5 mm, and most preferably about 2 mm.

73. A lithium-ion battery in the form of a flexible wire comprising: at least one anode and at least one cathode, wherein each anode and each cathode are independently the anode and the cathode as defined in any one of claims 1 to 72, wherein each anode and each cathode are coated with an electrolyte, wherein each electrolyte is independently the electrolyte as defined in any one of claims 1 to 72; and

74. The lithium-ion battery of claim 73, wherein the at least one anode and the at least one cathode comprise multiple anodes and/or multiple cathodes, and the at least one anode and the at least one cathode are woven together like a braid or a weave.

75. A method of manufacturing a lithium-ion battery in the form of a flexible wire, the method comprising the step of weaving an anode and a cathode together to form the lithium-ion battery in the form of the flexible wire.

76. The method of claim 75, wherein the lithium-ion battery is the lithium-ion battery defined in any one of claims 1 to 74.

77. The method of claim 75 or 76, wherein the weaving step is performed by twisting the anode and the cathode together, by wrapping the anode around the cathode, or by wrapping the cathode around the anode.

78. The method of claim 77, wherein the weaving step is performed by twisting the anode and the cathode together.

79. The method of any one of claims 75 to 78, wherein the weaving step is performed using a jig, or by hand.

80. The method of claim 79, wherein the weaving step is performed using a jig.

81. The method of any one of claims 75 to 80, further comprising a step of coating the anode and/or the cathode with an electrolyte before the weaving step.

82. The method of claim 81 , wherein the electrolyte is as defined in any one of claims 1 to 74.

83. The method of claim 81 or 82, wherein the electrolyte coating step is performed using casting or a dip- and-dry technique.

84. The method of claim 83, wherein the electrolyte coating step is performed using a dip-and-dry technique.

85. The method of any one of claims 81 to 84, further comprising a step of fabricating the anode and/or the cathode before electrolyte coating step.

86. The method of claim 85, wherein the fabricating of the anode comprises coating a conductive wire core with a coating, and the step of fabricating the cathode comprises coating a conductive wire core with a coating.

87. The method of claim 86, wherein the coating for the anode and/or the cathode are as defined in any one of claims 1 to 74.

88. The method of any one of claims 85 to 87, wherein the fabricating step is performed using physical vapor deposition, or a dip-and-dry technique.

89. The method of claim 88, wherein the fabricating step is performed using a dip-and-dry technique.

90. The method of any one of claims 75 to 89, further comprising a step of adding a contact liquid to the anode and cathode after the weaving step.

91. The method of claim 90, wherein the contact liquid is as defined in any one of claims 63 to 65.

92. The method of claim 90 or 91 , wherein the adding of the contact liquid is performed by wetting the electrolytes with a few drops of the contact liquid.

93. The method of any one of claims 75 to 92, further comprising a step of encapsulating the lithium-ion battery with an outer covering at least after the weaving step.

94. The method of claim 93, wherein the outer covering is as defined in any one of claims 66 to 68.

95. The method of claim 93 or 94, wherein the encapsulating step is performed by encapsulating, partially or completely, the lithium-ion battery with a heat-shrinkable tube, and heating the heat-shrinkable tube at a sufficient temperature and for a sufficient amount of time such that the heat-shrinkable tube shrinks around the lithium-ion battery.

96. The method of claim 95, wherein the heat-shrinkable tube is heated at 120 Q for 60 seconds.

97. The method of claim 93 or 94, wherein the encapsulating step is performed by coating the LIB partially or fully with at least one heat or UV curable resin.

98. The method of claim 97, wherein the coating step is performed by dipping the LIB into a monomer and then curing said monomer.

99. The method of any one of claims 75 to 98, wherein the weaving step comprises weaving at least one additional anode and/or at least one additional cathode with the anode and cathode to form the lithium-ion battery of claim 73 or 74.

100. Use of the lithium-ion battery defined in any one of claims 1 to 74 in wearable technology, textiles, and/or a compact power source unit.

101. The use of claim 100, wherein the lithium-ion battery has been woven into the textile or wearable technology.

102. The use of claim 100 or 101 , wherein the textile is clothing.

103. Use of the lithium-ion battery defined in any one of claims 1 to 74 in a medical device, a cell phone, smart packaging (including an RFID tag), or a sensor.

104. Use of the lithium-ion battery defined in any one of claims 1 to 74 in an aeronautic structural deformation sensor.

105. Use of the lithium-ion battery defined in any one of claims 1 to 74 in an on-garment display, a wearable sensor for sports or medicine, a virtual-reality device, a smart phone, or a smart watch or bracelet.