US20210184210A1

US20210184210A1 - Anode material for rechargeable li-ion batteries

Info

Publication number: US20210184210A1
Application number: US17/048,467
Authority: US
Inventors: Ping Liu; Haodong LIU
Original assignee: University of California
Current assignee: University of California
Priority date: 2018-04-16
Filing date: 2019-04-16
Publication date: 2021-06-17
Also published as: WO2019204359A1; US20230317937A1

Abstract

Materials, designs, methods of manufacture, and devices are provided for an anode material for a rechargeable lithium-ion battery. For example, an anode material may include Li_3±xV_2±yO_5±z. 0≤x≤7, 0≤y≤1, and z may be based on the charge resulting from Li_3±xand V_2±y. Also, a cell can include a lithiated anode material. The lithiated anode material may include Li3±xV2±yO5±z. The lithiated anode material may be casted on a first substrate to form a lithiated anode, having a separator stacked on the lithiated anode. The separator may include electrolytes. A cathode can be stacked on the separator. The cathode being formed by casting a cathode material on a second substrate.

Description

REFERENCE TO RELATED APPLICATIONS

The present application is a U.S. national phase of PCT International Patent Application No. PCT/US2019/027755, filed Apr. 16, 2019 and titled “ANODE MATERIAL FOR RECHARGEABLE LI-ION BATTERIES”, which also claims priority to U.S. Provisional Patent Application No. 62/658,558, filed Apr. 16, 2018 and titled “ANODE MATERIAL FOR RECHARGEABLE LI-ION BATTERIES,” which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present disclosure is generally related to Li-ion batteries. In particular, embodiments of the present disclosure relate to an anode material for fast charging rechargeable Li-ion batteries and processes for using the same.

BACKGROUND

While Li-ion batteries provide a low maintenance, high energy density battery, compared to other battery types, Li-ion batteries take too long to charge. Moreover, current Li-ion batteries with graphite as the anode are prone to lithium plating during rapid charging, which may lead to shorting or other aging/charging issues.

BRIEF DESCRIPTION OF THE EMBODIMENTS

Disclosed are materials, designs, methods of manufacture, and devices that relate to a fast charging rechargeable Li-ion battery. An anode material may include Li_3±xV_2±yO_5±z. 0≤x≤7, 0≤y≤1, and z may be based on the charge resulting from Li_3±xand V_2±y.
In embodiments, the Li_3±xV_2±yO_5±zmay be an omega structure. The omega structure may be a disordered rocksalt structure in the Fm3m space group.
In embodiments, lithium may be reversibly inserted to form at least one of Li₄V_2±yO_5±zand Li₅V_2±yO_5±z.
In embodiments, the Li₄V_2±yO_5±zor Li₅V_2±yO_5±zmay be an omega structure. The omega structure may be a disordered rocksalt structure in the Fm3m space group.
In embodiments, the anode material may further include one or more materials selected from the group of silicon, tin, graphite, or non-graphitized carbon. The one or more materials may be blended with the anode material.
In embodiments, the cathode may be selected from the group including one or more of one or more of LiMn₂O₄, LiNi_xCo_yMn_zO₂where x+y+z=1, or other cathodes.
In embodiments, the anode material may further include repeating the above steps to form a pouch-type cell.
Additional aspects of the present disclosure relate to an anode material. The anode material may include a composition. The composition may include Li₃V_xM_yO_5±z. M may be a dopant. 0.5<x<2, 0<y<1, and z may be based on a charge from Li₃, V_x, and M_y.
In embodiments, the Li₃V_xM_yO_5±zmay be an omega structure. The omega structure may be a disordered rocksalt structure in the Fm3m space group.
In embodiments, the anode material may further include reversibly inserting lithium to form Li₄V_xM_yO_5±zor Li₅V_xM_yO_5±z.
In embodiments, the Li₄V_xM_yO_±zor Li₅V_xM_yO_±zmay be an omega structure. The omega structure may be a disordered rocksalt structure in the Fm3m space group.
In embodiments, the anode material may further include one or more materials selected from the group of silicon, tin, graphite, or non-graphitized carbon. The one or more materials may be blended with the anode material.
In embodiments, the dopant may be selected from the group including one or more of Mg, Ca, Sc, B, Y, Al, Ti, Zr, Nb, Ta, Cr, Mo, or W.
In embodiments, the Li₃V_xM_yO_5±zmay be paired with a cathode.
In embodiments, the cathode may be selected from the group including one or more of LiMn₂O₄, LiNi_xCo_yMn_zO₂where x+y+z=1, or other cathodes.
In embodiments, the anode material may further include repeating the above steps to form a pouch-type cell.
In embodiments, the cell may be rolled to form a cylinder cell.
In embodiments, the anode may be paired with conductive additives and binders.
In embodiments, the conductive additives may include conductive carbon additives.
Additional aspects of the present disclosure relate to an anode material including a composition. The composition may include Li_3±XV_2±YM_yO_5±Z. M may be a dopant. 0<x<2, 0<y<1, and z may be based on a charge from Li_3±X, V_2±Y, and M_y.
Additional aspects of the present disclosure relate to a cell. The cell may include a lithiated anode material. The lithiated anode material may include Li_3±xV_2±yO_5±z. 0≤x≤7, 0≤y≤1, and z may be based on the charge resulting from Li_3±xand V_2±y. The lithiated anode material may be casted on a first substrate to form a lithiated anode. The cell may include a separator stacked on the lithiated anode. The separator may include electrolytes. The cell may include a cathode stacked on the separator. The cathode may be formed by casting a cathode material on a second substrate. The cell may include a packet foil surrounding the lithiated anode, the separator, and the cathode.
Additional aspects of the present disclosure relate to a method of manufacturing a cell. The method may include forming a lithiated anode material by applying a reducing agent to a powder. The lithiated anode material may include an omega structure Li₃V₂O₅. The omega structure may be a disordered rocksalt structure in the Fm3m space group. The reducing agent may include lithium. The powder may include Li₃V₂O₅. The method may include casting the lithiated anode material on a first substrate to form a lithiated anode. The method may include casting a cathode material on a second substrate to form a cathode. The method may include stacking a separator on the lithiated anode. The method may include stacking a cathode on the separator.
In embodiments, the first substrate may include copper.
In embodiments, the lithiated anode may further include one or more materials selected from the group of silicon, tin, graphite, or non-graphitized carbon.
In embodiments, the cathode may be selected from the group including one or more of LiMn₂O₄and LiNi_xCo_yMn_zO₂, where x+y+z=1.
In embodiments, the second substrate may include aluminum.
Additional aspects of the present disclosure relate to a method of manufacturing a cell. The method may include casting an anode material on a first substrate to form an anode. The anode material may include V₂O₅. The method may include casting a cathode material on a second substrate to form a cathode. The method may include stacking a separator on the anode. The method may include stacking the cathode on the separator. The method may include applying an electrode to the anode to synthesize the anode into a lithiated anode. The electrode may include lithium. The lithiated anode may include an omega structure Li₃V₂O₅. The omega structure may be a disordered rocksalt structure in the Fm3m space group.
Additional aspects of the present disclosure relate to a method of manufacturing a lithiated anode. The method may include casting an anode material on a first substrate to form an anode. The anode material may include V₂O₅. The method may include pressing lithium on the anode to form a pressed anode. The method may include casting a cathode material on a second substrate to form a cathode. The method may include stacking a separator on the pressed anode. The method may include stacking the cathode on the separator. The method may include injecting the separator with electrolytes, thereby synthesizing the pressed anode into a lithiated anode.
Additional aspects of the present disclosure relate to a method of manufacturing a cell. The method may include forming a lithiated anode material by applying a reducing agent to a powder. The lithiated anode material may include an omega structure Li₃V₂O₅. The omega structure may be a disordered rocksalt structure in the Fm3m space group. The reducing agent may include lithium. The powder may include Li₃V₂O₅. The method may include casting the lithiated anode material on a first substrate to form a lithiated anode.
In embodiments, the method may further include casting a cathode material on a second substrate to form a cathode. The method may further include stacking a separator on the lithiated anode. The method may further include stacking a cathode on the separator.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are disclosed herein and described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict typical or example embodiments of the disclosed technology. These drawings are provided to facilitate the reader's understanding of the disclosed technology and shall not be considered limiting of the breadth, scope, or applicability thereof. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale.

FIG. 1 illustrates a graph indicating the stability of the V₂O₅and Li₃V₂O₅electrode over multiple cycles in accordance to one embodiment of the present disclosure.

FIG. 2 illustrates a graph of voltage profiles indicating the stability of the Li₃V₂O₅electrode over multiple cycles in accordance to one embodiment of the present disclosure.

FIG. 3 illustrates a graph indicating the stability of the Li₃V₂O₅electrode after more than 1000 cycles in accordance to one embodiment of the present disclosure.

FIG. 4 illustrates a graph of voltage profiles indicating the stability of the Li₃V₂O₅electrode after more than 1000 cycles in accordance to one embodiment of the present disclosure.

FIG. 5 illustrates an X-ray diffraction (XRD) graph indicating the stability of the Li₃V₂O₅electrode, the rocksalt structure is well maintained through Li₃V₂O₅to Li₅V₂O₅in accordance to one embodiment of the present disclosure.

FIG. 6 illustrates an image captured using a scanning electron microscope (SEM) before cycling an anode, in accordance to one embodiment of the present disclosure.

FIG. 7 illustrates an image captured using a SEM before cycling an anode, in accordance to one embodiment of the present disclosure.

FIG. 8 illustrates an image captured using a SEM before cycling an anode, in accordance to one embodiment of the present disclosure.

FIG. 9 illustrates an image captured using a SEM before cycling an anode, in accordance to one embodiment of the present disclosure.

FIG. 10 illustrates an image captured using a scanning electron microscope (SEM) after cycling the anode of FIG. 6, in accordance to one embodiment of the present disclosure.

FIG. 11 illustrates an image captured using a SEM after cycling the anode of FIG. 7, in accordance to one embodiment of the present disclosure.

FIG. 12 illustrates an image captured using a SEM after cycling the anode of FIG. 8, in accordance to one embodiment of the present disclosure.

FIG. 13 illustrates an image captured using a SEM after cycling the anode of FIG. 9, in accordance to one embodiment of the present disclosure.

FIG. 14 illustrates a graph of voltage profiles of a second generation Li₃V₂O₅electrode under different current density in accordance to one embodiment of the present disclosure.

FIG. 15 illustrates a neutron diffraction of an anode and the corresponding crystal structure model, in accordance with various embodiments of the present disclosure.

FIG. 16 illustrates a neutron diffraction of an anode in various states, in accordance with various embodiments of the present disclosure.

FIG. 17 illustrates an image of an omega structure of an anode, in accordance with various embodiments of the present disclosure.

FIG. 18 illustrates an image of an omega structure of an anode, in accordance with various embodiments of the present disclosure.

FIG. 19 illustrates an image of an omega structure of an anode, in accordance with various embodiments of the present disclosure.

FIG. 20 illustrates an image of a lithiated structure of the anode of FIG. 17, in accordance with various embodiments of the present disclosure.

FIG. 21 illustrates an image of a lithiated structure of the anode of FIG. 18, in accordance with various embodiments of the present disclosure.

FIG. 22 illustrates an image of a lithiated structure of the anode of FIG. 19, in accordance with various embodiments of the present disclosure.

FIG. 23 illustrates an example cell configuration, in accordance with various embodiments of the present disclosure.

FIG. 24 illustrates an example cell configuration, in accordance with various embodiments of the present disclosure.

FIG. 25 illustrates an example cell configuration, in accordance with various embodiments of the present disclosure.

FIG. 26 is an operational flow diagram illustrating various operations that may be performed in accordance with embodiments of the disclosure.

FIG. 27 is an operational flow diagram illustrating various operations that may be performed in accordance with embodiments of the disclosure.

FIG. 28 is an operational flow diagram illustrating various operations that may be performed in accordance with embodiments of the disclosure.

FIG. 29 is a graph illustrating performance of an example cell, in accordance with various embodiments of the present disclosure.

FIG. 30 is a graph illustrating voltage profiles of an example cell, in accordance with various embodiments of the present disclosure.

FIG. 31 illustrates graph 3100 of cycling performance of a second generation Li₃V₂O₅electrode under different current density in accordance to one embodiment of the present disclosure.

The figures are not intended to be exhaustive or to limit the invention to the precise form disclosed. It should be understood that the invention can be practiced with modification and alteration, and that the disclosed technology be limited only by the claims and the equivalents thereof.

DETAILED DESCRIPTION

In the past decades, rechargeable Li-ion batteries have made mobile devices and personal computers an essential necessity in a modern day society. While important advancements in battery technology (e.g., energy density and structural stability) have continued, fast charging is an area that still requires significant advances for Li-ion batteries. Li-ion batteries may possess high energy density; however, the rate at which the battery can charge may be affected by the corresponding anode material of the battery.
Currently, graphite is used as an anode and operates at a potential similar to lithium metal plating (about 90 mV). Under rapid charging, the lithium metal plates onto the graphite surfaces, which leads to capacity fading, potential internal shorting, and safety incidents. Lithium titanium oxide (Li₄Ti₅O₁₂) may also be used as an anode. Lithium titanium oxide may be capable of rapid charging. However, lithium ion batteries using lithium titanium oxide have a cell voltage of about 1.4 V less than that of graphite-based cells. The cell voltage may be reduced from about 3.7 V to about 2.3 V. Thus, an anode material with a high rate capability that operates between about 0.1V and about 1V is disclosed.
Disclosed are materials, designs, methods of manufacture, and devices related to fast-charging Li-ion batteries. The fast-charging Li-ion battery may include substrates, an anode material, a cathode, an electrolyte, a separator, and a packet foil. The Li-ion batteries may be able to charge on the scale of minutes instead of hours. The battery may be one or more of a pouch-type, cylinder, button, prismatic, or other battery types. In embodiments, the cell may be formed to have the specifications as listed in Table 1. All of the values listed in this disclosure are approximate, unless expressly indicated otherwise.

TABLE 1

Cell design for 2 Ah pouch cell.

Dimension	Thickness, max (mm)	4.5
Cathode	Capacity (mAh/g)	190
	Active Material Loading	90%
	Coating Weight (mg/cm²each side)	14.3
	Areal Capacity	2.45
	(mAh/cm²each side)
	Electrode Press Density (g/cm³)	2.86
	Electrode Length (mm)	56
	Electrode Width (mm)	43
	Electrode Thickness (single side)	45
	(um)
	Al Foil Thickness (um)	15
	Double Layers	17
Anode	Cell Balance (N/P ratio)	1.08
	Capacity (mAh/g)	300
	Active Material Loading	90%
	Coating Weight (mg/cm²each side)	9.8
	Areal Capacity	2.64
	(mAh/cm²each side)
	Electrode Press Density (g/cm³)	2.26
	Electrode Length (mm)	58
	Electrode Width (mm)	45
	Electrode Thickness (single side)	39
	(um)
	Cu Foil Thickness (um)	10
	Double Layers	18
Electrolyte	Electrolyte/Capacity (g/Ah)	3
	Weight (g)	6
Separator	Total Wrapping Length (mm)	1750
	Thickness (um)	20
Packet Foil	Thickness (um)	115
Cell	Voltage (V)	3.2
	Capacity (mAh)	2031
	Energy (mWh)	6499
	Weight (g)	~32
	Energy density (Wh/kg)	>200

For example, a battery may be used for powering personal electronics to cars, neighborhoods, and other systems. A battery may include a group of cells. Cells may be individual electrochemical units including individual assemblies. In some embodiments, the cell voltage may range from about 1 volt to about 5 volts. In embodiments, the capacity may range from about 1500 mAh to about 50000 mAh. In some embodiments, the cell may have an energy ranging from about 1500 mWh to about 250000 mWh. In some embodiments, the cell may have an energy density ranging from about 150 Wh/kg to about 500 Wh/kg.
The cell may include a cathode. The cathode may include one or more of LiMn₂O₄, LiNi_xCo_yMn_zO₂where x+y+z=1, and other cathodes. The cathode may be paired with a given anode based on corresponding compositions.
In embodiments, the cathode may have a capacity ranging from about 50 mAh/g to about 300 mAh/g. In some embodiments, the active material loading may range from about 50% to about 100%. In embodiments, the coating weight for each side may range from about 3 mg/cm²to about 25 mg/cm². In some embodiments, the areal capacity may represent the energy capacity as a function of the size of a given battery. The areal capacity for each side of the cathode may range from about 0.5 mAh/cm²to about 10 mAh/cm².
In some embodiments, the cathode press density may range from about 0.5 g/cm³to about 10 g/cm³. Aluminum foil may be used as a substrate upon which to place the cathode material. In embodiments, the cathode material may be cast, laminated, pressed, or otherwise coupled to the aluminum foil. In some embodiments, the aluminum foil thickness may range from about 1 um to about 50 um. It should be appreciated that other materials may be used as a substrate for the cathode. The number of double layers may range from about 5 to about 50.
As described above, the cell may include anode material. The anode material may be able to facilitate a Li-ion battery charging on the scale of minutes without a complicated nanosizing process. The anode material could enable a fast charge battery without sacrificing energy density. In embodiments, the anode material may show a voltage plateau ranging from about 0 V to about 1 V. In some embodiments, the voltage plateau may be about 0.5 V. The range of the voltage potential may ensure that under high current, the electrode potential achieves a value that does not cause lithium plating. The range of the voltage potential may also ensure that the cell voltage does not decrease to less than about 3.0 V, when a common cathode material is used. The anode material may work at a voltage at about 0.5V, which reduces the risk of lithium plating but results in a lithium-ion battery with cell voltage about 1V higher than that with a Li₄Ti₅O₁₂anode, as discussed above.
In embodiments, the anode material includes V₂O₅. In some embodiments, the V₂O₅electrode may be lithiated. Lithiating may include treating a material or substance with lithium or one of its compounds. In some embodiments, the lithiated V₂O₅may form one or more of Li₃V₂O₅, Li₅V₂O₅, and other compositions with the general formula Li_xV₂O₅, where 3≤x≤5. The Li₃V₂O₅may be introduced as an anode material that enables two lithium to be reversibly inserted to form Li₅V₂O₅. In some embodiments, inserting lithium into the V₂O₅can form an omega structure Li₃V₂O₅, which may be a disordered rocksalt structure in the Fm3m space group. The rocksalt structure may be well maintained from Li₃V₂O₅to Li₅V₂O₅, which can be indexed in the cubic system (a=4.1 Å).
In some embodiments, Li₃V₂O₅may represent a base composition to which dopants may be added. The composition may have a rocksalt structure, into which two more lithium can be inserted into Li₃V₂O₅to form a nominal composition of Li₅V₂O₅, where the rocksalt structure is still preserved in the Li₅V₂O₅composition. The general formula for the composition may be Li_3±xV_2±yM_yO_5±z, wherein 0≤x≤7, 0≤y≤2, and where z depends on the combined positive charge of Li, V and M so that the oxygen balances out the combined positive charge. M may be a dopant used in addition to, or instead of, V. In some embodiments, the dopants may include one or more metal dopants. The metal dopants may include one or more divalent, trivalent, tetravalent, pentavalent, or hexavalent dopants, such as Mg, Ca, Sc, B, Y, Al, Ti, Zr, Nb, Ta, Cr, Mo, W, or other metal dopants.
The omega structure may be a disordered rocksalt structure in the Fm3m space group with octahedral and tetrahedral sites. The crystal structure model may include oxygen ions, Li_tet, Li/V_oct, lithium and vanadium ions, and lithium ions. Oxygen ions may be closely-packed serving as a frame for the omega structure of Li₃V₂O₅. In embodiments, the oxygen ions may be located at the corners and face centers of the crystal structure. In some embodiments, lithium ions and vanadium ions may be located at the edge centers of the crystal structure. In embodiments, the lithium and vanadium ions may sit in the octahedral sites coordinated. In some embodiments, the lithium ions may occupy the tetrahedral sites. The omega structure is discussed in greater detail below.
In embodiments, the anode may include active materials, conductive carbon additives, binders, and additional Li sources. In some embodiments, active material may include one or more of the above disclosed anode materials and other active materials. In embodiments, conductive additives may improve the life cycle of a cell as well as the energy density of a cell. Conductive carbon additives may include one or more of carbon nanotubes, carbon blacks, ultra-fine carbon, and other carbon additives. In some embodiments, binders may hold active material together as well as place them in contact with the foil corresponding to an electrode. The binders may also help keep conductive carbon additives in place against the active material. The binders may include one or more of homopolymers, copolymers, polyvinylidene fluoride, styrene butadiene copolymer, and other binders.
In some embodiments, the anode may have a negative to positive electrode (N to P) ratio, ranging from about 0.8 to about 1.5. In embodiments, the anode may have a capacity ranging from about 100 mAh/g to about 500 mAh/g. In some embodiments, the active material loading may range from about 50% to about 100%. In embodiments, the coating weight for each side may range from about 3 mg/cm²to about 25 mg/cm². In some embodiments, the areal capacity for each side of the anode may range from about 0.5 mAh/cm²to about 10 mAh/cm².
In some embodiments, the electrode press density may range from about 0.5 g/cm³to about 10 g/cm³. Copper foil may be used as a substrate upon which to place the anode material. In embodiments, the anode material may be cast, laminated, pressed, or otherwise coupled to the copper foil. In some embodiments, the copper foil thickness may range from about 1 um to about 200 um. It should be appreciated that other materials may be used as a substrate for the anode. In embodiments, the number of double layers may range from about 5 to about 50.
Electrolytes may be used to fill the separator that promotes the movement of ions between the cathode and the anode during charge and discharge (e.g., during charge the ions move from cathode to anode; while discharging the ions move from anode to cathode). In some embodiments, the electrolyte may have an electrolyte/capacity value ranging from about 1 g/Ah to about 10 g/Ah. In some embodiments, the electrolytes may include organic solvents selected from one or more of ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and other organic solvents. The electrolytes may further include lithium salts, such as LiPF₆, LiClO₄, LiBF₄, LiAsF₆, LiTFSI, LiFSI, and other salts. TFSI may refer to bis(trifluoromethanesulfonyl)imide and FSI refers to Bis(fluorosulfonyl)imide.
The separator may insulate the cathode from the anode. The separator may have no electrical conductivity. The separator may be made of one or more of rubber, glass fiber, cellulose, polyethylene plastic, polyolefin, and other materials. The separator may be porous to hold the electrolyte. In some embodiments, the pore size ranges from about 10 nm to about 150 nm. The separator may be made to close the pores when the temperature breaches a threshold to prevent the reaction from escalating. In some embodiments, the separator may be coated with another material that will close over the pores to prevent overheating.
The packet foil may insulate the anode-separator-cathode assembly from an external environment. The packet foil may range from about 50 um to about 200 um.
It should be appreciated that while individual values within the ranges need not be achieved, the ratios between one or more values may be relevant in scaling the cell for different applications. The ranges are provided as example embodiments of cells for a given application, and it should be appreciated that different ranges may be appropriate for different applications.
FIG. 1 illustrates graph 100 indicating the stability of the V₂O₅electrode over multiple cycles in accordance to one embodiment of the present disclosure. As illustrated, the capacity of the battery using a V₂O₅electrode stays substantially consistent around 100 mAh/g for multiple cycles of charging and discharging. In the first set of cycles, the electrode material was discharged to about 0.01V and charged to about 3.0 V and lost some capacity. As illustrated, the V₂O₅electrode first discharges at around 800 mAh/g and before the 10th charge the specific capacity moves to about 300 mAh/g. The second set of cycles discharged to about 0.01V and charged to about 2.0 V and substantially maintained the capacity around 100 mAh/g. The test used to generate the graph used a current density of about 100 mA/g.
FIG. 2 illustrates graph 200 of voltage profiles indicating the stability of the Li₃V₂O₅electrode over multiple cycles in accordance to one embodiment of the present disclosure. As illustrated, the voltage profiles remain substantially the same over multiple charges and discharges. The test may be substantially similar to the test as described in FIG. 1. The voltage profiles may more clearly indicate that the specific capacity is maintained at around 110 mAh/g for both charges and discharges.
FIG. 3 illustrates graph 300 indicating the stability of the Li₃V₂O₅electrode after more than 1000 cycles in accordance to one embodiment of the present disclosure. As illustrated, the capacity of the Li₃V₂O₅electrode stays substantially consistent over about 1000 cycles. Graph 300 also indicates an operating potential of about 0.5 V and a capacity of about 280 mAh/g. The electrode could achieve high capacity greater than about 10 C current density, which translates to less than about six minutes of charge time. As illustrated, the electrode material maintains stable structure over long term cycling. The battery using this anode material could improve expected energy density by about 85%.
In the first 100 or so cycles, the anode material was subjected to a current density of about 100 mA/g where the greatest loss in capacity is shown. In the remaining cycles, a current density of about 200 mA/g is used and the capacity is shown as staying substantially around 90 mAh/g.
FIG. 4 illustrates graph 400 of voltage profiles indicating the stability of the Li₃V₂O₅electrode after more than 1000 cycles in accordance to one embodiment of the present disclosure. As illustrated, the voltage profiles remain substantially the same over about 1000 charges and discharges. The anode used for testing may be substantially similar to the one described in FIG. 3. The voltage profile may more clearly indicate the effect of charges or discharges, or the lack of effect, on the specific capacity over the 1000 or so cycles. As illustrated, the first set of cycles provided a greater specific capacity for charge and discharge around 110 mAh/g. Around the 67^thcycle, a current density of about 200 mA/g is used and the specific capacity lowers to about 90 mAh/g. For the next 1000 or so cycles, the specific capacity stays around 90 mA/g.
FIG. 5 illustrates X-ray diffraction (XRD) graph 500 indicating the stability of the Li₃V₂O₅electrode in accordance to one embodiment of the present disclosure. As illustrated, the XRD graph indicates the rocksalt structure is maintained from Li₃V₂O₅to Li₅V₂O₅. The peak positions are not shifted during charge and discharge, which may indicate that the Li₃V₂O₅may be a low-strain material. Low-strain material may refer to minimal volume change to the material during charge and discharge. Even as the electrode material is charged to and discharged from 2 V, the XRD shows a similar rocksalt structure of the electrode material.
FIGS. 6-9 illustrate sets of images before cycling, in accordance with various embodiments of the present disclosure. The sets of images gathered using a scanning electron microscope (SEM) indicate pictures of a given anode material before a charge/discharge cycle.
FIGS. 10-13 illustrates sets of images after cycling, in accordance with various embodiments of the present disclosure. The sets of images gathered using a scanning electron microscope (SEM) indicate pictures of the given anode material of FIGS. 6-9 after the charge/discharge cycle. As illustrated, the anode material is substantially the same before cycling and after cycling, and the particles in the anode material remain a substantially similar size in each set of images and are otherwise minimally affected.
FIG. 14 illustrates graph 1400 of voltage profiles of a second generation Li₃V₂O₅electrode under different current density in accordance to one embodiment of the present disclosure. As illustrated, the discharge capacity of Li₃V₂O₅exceeds 300 mAh/g at 5 mA/g current density. There is almost no voltage hysteresis at 100 mA/g current density. Even at a high discharge current of 2.5 A/g, the material still shows a capacity of more than 125 mAh/g. 1402 may represent rate performance of a cell with 5 mA/g current capacity. 1404 may represent rate performance of a cell with 100 mA/g current capacity. 1406 may represent rate performance of a cell with 500 mA/g current capacity. 1408 may represent rate performance of a cell with 1000 mA/g current capacity. 1410 may represent rate performance of a cell with 2500 mA/g current capacity.
FIG. 15 illustrates neutron diffraction 1500 of an anode material and corresponding crystal structure model 1510, in accordance with various embodiments of the present disclosure. 1502 may represent observed values in the neuron diffraction of Li₃V₂O₅. 1502 may be illustrated as “x”s. 1504 may represent calculated values for the neuron diffraction values of Li₃V₂O₅. 1504 may be illustrated as a line. 1506 may represent the difference between the observed values and the calculated values, which stays substantially consistent. 1506 may be illustrated as a line. 1508 may represent rocksalt phases. 1508 may be illustrated as vertical bars. Peaks in 1502 and 1504 may correspond to 1508.
Crystal structure model 1510 may be the omega structure of Li₃V₂O₅. The omega structure may be similar to a disordered rocksalt structure with a Fm3m space group. 1511 may represent oxygen ions. 1512 may represent Li_tetand 1514 may represent Li/V_oct. 1511 may be a part of 1512 and 1514. 15111, 1512, 1514 may be part of crystal structure model 1510.
Oxygen ions 1511 may be close-packed in crystal structure model 1510, serving as a frame for the rocksalt structure of Li₃V₂O₅. In crystal structure model 1510, the oxygen ions 1511 may be located at the corners and face centers. Lithium ions and vanadium ions may be located at the edge centers, represented by the other spheres. The lithium and vanadium ions 1514 may sit in the octahedral sites coordinated by, as illustrated, six oxygen ions. Part of the lithium ions 1512 may occupy the tetrahedral sites coordinated by, as illustrated, four oxygen ions.
FIG. 16 illustrates neutron diffraction 1600 of an anode material in various states, in accordance with various embodiments of the present disclosure. 1602 may represent the neutron diffraction of Li₃V₂O₅. 1604 may represent discharging the rocksalt structure of Li₃V₂O₅to about 0.01 V. 1606 may represent charging the rocksalt Li₃V₂O₅to about 2.0 V. As illustrated, the cubic rocksalt phase is maintained during the charge and discharge. The structure may be highly reversible. In the lithiated state, the volume expansion of the cubic structure may be less than about 7%.
FIG. 17 illustrates an image of an omega structure of an anode material, in accordance with various embodiments of the present disclosure. The image may be taken using a microscope. The image may illustrate a face center cubic (FCC) structure.
FIG. 18 illustrates an image of an omega structure of an anode material, in accordance with various embodiments of the present disclosure. The image may be taken using a microscope. The image may illustrate a face center cubic (FCC) structure. 200 and 220 may represent the electron diffraction peaks of the anode material.
FIG. 19 illustrates an image of an omega structure of an anode material, in accordance with various embodiments of the present disclosure. The image may be taken using annular bright-field scanning transmission electron microscopy. The image may illustrate a face center cubic (FCC) structure. The atoms in the cubic structure are illustrated with the dots.
FIG. 20 illustrates an image of a lithiated structure of the anode material of FIG. 17, in accordance with various embodiments of the present disclosure. The image may be taken using a microscope. The image may illustrate that the rocksalt structure is maintained after lithiating the Li₃V₂O₅.
FIG. 21 illustrates an image of a lithiated structure of the anode material of FIG. 18, in accordance with various embodiments of the present disclosure. The image may be taken using a microscope. The image may illustrate that the rocksalt structure is maintained after lithiating the Li₃V₂O₅.
FIG. 22 illustrates an image of a lithiated structure of the anode material of FIG. 19, in accordance with various embodiments of the present disclosure. The image may be taken using annular bright-field scanning transmission electron microscopy. The image may illustrate that the rocksalt structure is maintained after lithiating the Li₃V₂O₅.
FIG. 23 illustrates example cell configuration 2300, in accordance with various embodiments of the present disclosure. The raw material may be V₂O₅. Cell 2300 may be based on an ex situ lithiation, or where the Li₃V₂O₅may be lithiated chemically before cell 2300 is made. Chemical lithiation may include applying a reducing agent to a V₂O₅powder. For example, the reducing agent may include n-Butyl lithium, sec-Butyl lithium, t-Butyl lithium, phenyllithium, and other reducing agents. The reducing agent may be mixed with the V₂O₅in stoichiometric amounts to obtain rocksalt Li₃V₂O₅. The rocksalt Li₃V₂O₅may be used as the anode of the cell. It should be appreciated that various well-understood fabrication methods may be used to incorporate the rocksalt Li₃V₂O₅as an anode of a cell. For example, the pre-fabricated rocksalt Li₃V₂O₅may be cast on, laminated to, pressed on, or otherwise coupled to a copper substrate to form the anode. A separator may be disposed onto the anode. A cathode material may be cast, pressed, laminated, or otherwise coupled on an aluminum substrate to form a cathode. The cathode may be disposed on the separator.
FIG. 24 illustrates example cell configuration 2400, in accordance with various embodiments of the present disclosure. Cell 2400 may be based on electrochemical lithiation, or synthesizing rocksalt Li₃V₂O₅by applying lithium to a manufactured cell with V₂O₅. Electrochemical lithiation may occur by applying an electrode (e.g., lithium) to cell 2400 on the back of the anode. This electrode may be the third electrode, as the anode and the cathode represent the first and second electrodes. As illustrated, the V₂O₅may be directly used as an anode material. It should be appreciated that various well-understood fabrication methods may be used to fabricate cell 2400. For example, the V₂O₅may be disposed on top of a first substrate (e.g., copper) to form an anode. A separator may be disposed on top of the anode. A cathode may be formed by coupling a cathode material to a second substrate. The cathode may be disposed on top of the separator. The electrochemical lithiation may occur by applying an electrode, such as lithium, to the bottom of the anode. The lithium electrode may be used to electrochemically lithiate the anodes of cell 2400 which converts the V₂O₅into rocksalt Li₃V₂O₅. The V₂O₅electrode and the lithium electrode may be connected for electrochemical lithiation. For example, the V₂O₅electrode may be the working electrode, and the lithium electrode may be the counter electrode. Discharging the V₂O₅electrode against the lithium electrode may achieve Li₃V₂O₅. After the lithiation, the V₂O₅electrode and the lithium electrode may be disconnected. The lithiated V₂O₅electrode may be used as the lithiated anode of the battery.
FIG. 25 illustrates an example cell configuration, in accordance with various embodiments of the present disclosure. Cell 2500 may be based on in-situ lithiation, or synthesizing the rocksalt Li₃V₂O₅by directly reacting the lithium with the V₂O₅inside cell 2500. As illustrated, the V₂O₅may be directly used as an anode. The V₂O₅may be cast, laminated, or otherwise coupled, to a substrate that may collect current. After the V₂O₅may be cast, lithium (e.g., powder, thin film, etc.) may be cast, pressed, or otherwise coupled, onto the laminated V₂O₅. The amount of lithium used may be based on stoichiometric ratios with V₂O₅. The in-situ lithiation process may be applied to every layer of the V₂O₅anode. The lithium may react with the V₂O₅after electrolyte injection and convert the electrodes to rocksalt Li₃V₂O₅.
FIG. 26 is operational flow diagram 2600 illustrating various operations that may be performed in accordance with embodiments of the disclosure. 2602 may include applying a reducing agent to a powder to synthesize a lithiated anode material. The reducing agent may include lithium. The powder may include V₂O₅. The lithiated anode material may be rocksalt Li₃V₂O₅in a Fm3m space group. 2604 may include casting the lithiated anode material on a first substrate to form the lithiated anode via ex-situ lithiation, as described herein. The first substrate may be copper. 2606 may include casting a cathode material on a second substrate to form a cathode. The second substrate may be aluminum. 2608 may include stacking a separator on the lithiated anode. 2610 may include stacking the cathode on the separator. It should be appreciated that flow diagram 2600 may be repeated multiple times to form stacked groups of cathode-separator-anode composites. These stacked groups may form a battery.
FIG. 27 is an operational flow diagram 2700 illustrating various operations that may be performed in accordance with embodiments of the disclosure. 2702 may include casting an anode material on a first substrate to form an anode. The anode material may be V₂O₅. 2704 may include casting a cathode material on a second substrate to form a cathode. 2706 may include stacking a separator on the anode. 2708 may include stacking the cathode on the separator. 2710 may include applying a third electrode to a bottom of the anode to synthesize a lithiated anode via electrochemical lithiation, as described herein. The third electrode may be lithium. The first substrate, the lithiated anode, the separator, the cathode material, and the second substrate may be substantially similar to FIG. 26. It should be appreciated that flow diagram 2700 may be repeated multiple times to form stacked groups of cathode-separator-anode composites. These stacked groups may form a battery.
FIG. 28 is operational flow diagram 2800 illustrating various operations that may be performed in accordance with embodiments of the disclosure. 2802 may include casting an anode material on a first substrate to form an anode. The anode material may be V₂O₅. 2804 may include pressing lithium on the anode to form a pressed anode. 2806 may include casting a cathode material on a second substrate to form a cathode. 2808 may include stacking a separator on the pressed anode. 2810 may include stacking the cathode on the separator. 2812 may include injecting the separator with electrolytes to synthesize the pressed anode into a lithiated anode. The first substrate, the lithiated anode the separator, the cathode, and the second substrate may be substantially similar to FIG. 26. It should be appreciated that flow diagram 2800 may be repeated multiple times to form stacked groups of cathode-separator-anode composites. These stacked groups may form a battery.
FIG. 29 is graph 2900 illustrating performance of an example cell, in accordance with various embodiments of the present disclosure. 2902 may represent charge capacity. 2904 may represent discharge capacity. 2906 may represent coulombic efficiency. As illustrated, the charge and discharge capacities are stable.
FIG. 30 is graph 3000 illustrating voltage profiles of an example cell, in accordance with various embodiments of the present disclosure. 3002 may illustrate a voltage profile at the 10th cycle. 3004 may illustrate a voltage profile at the 100th cycle. 3006 may illustrate a voltage profile at the 200th cycle. 3008 may illustrate a voltage profile at the 300th cycle. 3010 may illustrate a voltage profile at the 400th cycle. 3012 may illustrate a voltage profile at the 500th cycle. As illustrated, the discharge voltage begins at around 3.2 V for the about 500 cycles. The specific capacity stays at around 120 mAh/g over about 500 cycles. The voltage profiles illustrate consistent behavior of the cell over about 500 cycles.
FIG. 31 illustrates graph 3100 of cycling performance of a second generation Li₃V₂O₅electrode under different current density in accordance to one embodiment of the present disclosure. 3102 may represent a current density of about 1.0 A/g. 3104 may represent a current density of about 2.5 A/g. 3104 may represent a current density of about 5.0 A/g. 3104 may represent a current density of about 10.0 A/g. 3104 may represent a current density of about 20 A/g. Graph 3100 illustrates high stability and high rate capability over a thousand cycles.
While various embodiments of the disclosed technology have been described above, it should be understood that they have been presented by way of example only, and not of limitation. Likewise, the various diagrams may depict an example architectural or other configuration for the disclosed technology, which is done to aid in understanding the features and functionality that can be included in the disclosed technology. The disclosed technology is not restricted to the illustrated example architectures or configurations, but the desired features can be implemented using a variety of alternative architectures and configurations. It will be apparent to one of skill in the art how alternative functional, logical or physical partitioning and configurations can be implemented to implement the desired features of the technology disclosed herein. Additionally, with regard to flow diagrams, operational descriptions and method claims, the order in which the steps are presented herein shall not mandate that various embodiments be implemented to perform the recited functionality in the same order unless the context dictates otherwise.
Although the disclosed technology is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations, to one or more of the other embodiments of the disclosed technology, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus, the breadth and scope of the technology disclosed herein should not be limited by any of the above-described exemplary embodiments.
Terms and phrases used in this document, and variations thereof, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing: the term “including” should be read as meaning “including, without limitation” or the like; the term “example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof; the terms “a” or “an” should be read as meaning “at least one,” “one or more” or the like; and adjectives such as “conventional,” “traditional,” “normal,” “standard,” “known” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that may be available or known now or at any time in the future. Likewise, where this document refers to technologies that would be apparent or known to one of ordinary skill in the art, such technologies encompass those apparent or known to the skilled artisan now or at any time in the future.
The presence of broadening words and phrases such as “one or more,” “at least,” “but not limited to” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases may be absent.
Additionally, the various embodiments set forth herein are described in terms of exemplary block diagrams, flow charts and other illustrations. As will become apparent to one of ordinary skill in the art after reading this document, the illustrated embodiments and their various alternatives can be implemented without confinement to the illustrated examples. For example, block diagrams and their accompanying description should not be construed as mandating a particular architecture or configuration.

Claims

What is claimed is:

1. An anode material comprising Li_3±xV_2±yO_5±z, wherein 0≤x≤7, 0≤y≤1, and z is based on the charge resulting from Li_3±xand V_2±y.

2. The anode material of claim 1, wherein the Li_3±xV_2±yO_5±zis an omega structure, wherein the omega structure is a disordered rocksalt structure in the Fm3m space group.

3. The anode material of claim 1, wherein lithium is reversibly inserted to form at least one of Li₄V_2±yO_5±zand Li₅V_2±yO_5±z.

4. The anode material of claim 3, wherein the Li₄V_2±yO_5±zor Li₅V_2±yO_5±zis an omega structure, wherein the omega structure is a disordered rocksalt structure in the Fm3m space group.

5. The anode material of claim 1, further comprising one or more materials selected from the group of silicon, tin, graphite, or non-graphitized carbon, wherein the one or more materials are blended with the anode material.

6. The anode material of claim 1, wherein the cathode is selected from the group comprising one or more of one or more of LiMn₂O₄, LiNi_xCo_yMn_zO₂where x+y+z=1, or other cathodes.

7. The anode material of claim 1, further comprising repeating the above steps to form a pouch-type cell.

8. An anode material comprising a composition defined by Li₃V_xM_yO_5±z, wherein M is a dopant, and wherein 0.5<x<2, 0<y<1, and z is based on a charge from Li₃, V_x, and M_y.

9. The anode material of claim 8, wherein the Li₃V_xM_yO_5±zis an omega structure, wherein the omega structure is a disordered rocksalt structure in the Fm3m space group.

10. The anode material of claim 8, further comprising reversibly inserting lithium to form Li₄V_xM_yO_5±zor Li₅V_xM_yO_5±z.

11. The anode material of claim 10, wherein the Li₄V_xM_yO_5±zor Li₅V_xM_yO_5±zis an omega structure, wherein the omega structure is a disordered rocksalt structure in the Fm3m space group.

12. The anode material of claim 8, further comprising one or more materials selected from the group of silicon, tin, graphite, or non-graphitized carbon, wherein the one or more materials are blended with the anode material.

13. The anode material of claim 8, wherein the dopant is selected from the group comprising one or more of Mg, Ca, Sc, B, Y, Al, Ti, Zr, Nb, Ta, Cr, Mo, or W.

14. The anode material of claim 8, wherein the Li₃V_xM_yO_5±zis paired with a cathode.

15. The anode material of claim 14, wherein the cathode is selected from the group comprising one or more of LiMn₂O₄, LiNi_xCo_yMn_zO₂where x+y+z=1, or other cathodes.

16. The anode material of claim 8, further comprising repeating the above steps to form a pouch-type cell.

17. The anode material of claim 8, wherein the cell is rolled to form a cylinder cell.

18. The anode material of claim 8, wherein the anode is paired with conductive additives and binders.

19. The anode material of claim 18, wherein the conductive additives comprises conductive carbon additives.

20. An anode material comprising a composition defined by Li_3±XV_2±YM_yO_5±Z, wherein M is a dopant, and wherein 0<x<2, 0<y<1, and z is based on a charge from Li_3±X, V_2±Y, and M_y.

21. A cell, comprising

a lithiated anode material, wherein the lithiated anode material comprises Li_3±xV_2±yO_5±z, wherein 0≤x≤7, 0≤y≤1, and z is based on the charge resulting from Li_3±xand V_2±y, wherein the lithiated anode material is casted on a first substrate to form a lithiated anode;

a separator stacked on the lithiated anode, wherein the separator includes electrolytes;

a cathode stacked on the separator, wherein the cathode is formed by casting a cathode material on a second substrate; and

a packet foil surrounding the lithiated anode, the separator, and the cathode.

22. A method of manufacturing a cell, the method comprising:

forming a lithiated anode material by applying a reducing agent to a powder, wherein the lithiated anode material comprises an omega structure Li₃V₂O₅, wherein the omega structure is a disordered rocksalt structure in the Fm3m space group, wherein the reducing agent comprises lithium, and wherein the powder comprises Li₃V₂O₅;

casting the lithiated anode material on a first substrate to form a lithiated anode;

casting a cathode material on a second substrate to form a cathode;

stacking a separator on the lithiated anode; and

stacking a cathode on the separator.

23. The method of claim 22, wherein the first substrate comprises copper.

24. The method of claim 22, wherein the lithiated anode further comprises one or more materials selected from the group of silicon, tin, graphite, or non-graphitized carbon.

25. The method of claim 22, wherein the cathode is selected from the group comprising one or more of LiMn₂O₄and LiNi_xCo_yMn_zO₂, where x+y+z=1.

26. The method of claim 22, wherein the second substrate comprises aluminum.

27. A method of manufacturing a cell, the method comprising:

casting an anode material on a first substrate to form an anode, wherein the anode material comprises V₂O₅;

casting a cathode material on a second substrate to form a cathode;

stacking a separator on the anode;

stacking the cathode on the separator; and

applying an electrode to the anode to synthesize the anode into a lithiated anode, wherein the electrode comprises lithium, wherein the lithiated anode comprises an omega structure Li₃V₂O₅, and wherein the omega structure is a disordered rocksalt structure in the Fm3m space group.

28. A method of manufacturing a lithiated anode, the method comprising:

pressing lithium on the anode to form a pressed anode;

casting a cathode material on a second substrate to form a cathode;

stacking a separator on the pressed anode;

stacking the cathode on the separator; and

injecting the separator with electrolytes, thereby synthesizing the pressed anode into a lithiated anode.

29. A method of manufacturing a cell, the method comprising:

casting an anode material on a first substrate to form an anode, wherein the anode material comprises V₂O₅

forming a lithiated anode by applying a reducing agent to an anode, wherein the lithiated anode comprises an omega structure Li₃V₂O₅, wherein the omega structure is a disordered rocksalt structure in the Fm3m space group, wherein the reducing agent comprises lithium, and wherein the anode comprises Li₃V₂O₅.

30. The method of claim 29, further comprising:

casting a cathode material on a second substrate to form a cathode;

stacking a separator on the lithiated anode; and

stacking a cathode on the separator.