Method and system for silicon-based lithium-ion cells with controlled silicon lithiation

Abstract

The present invention provides a system and / or method for silicon-based lithium-ion cells in which the lithiation of silicon is controlled. [Solution] The anode contains silicon lithified to a post-discharge level configured to exceed a minimum threshold level, the minimum threshold for lithiation being 3% silicon lithiation. The silicon lithiation level after charging the battery is in the range of 30% to 95% silicon lithiation, 30% to 75% silicon lithiation, 30% to 65% silicon lithiation, or 30% to 50% silicon lithiation. The silicon lithiation level after discharging the battery is in the range of 3% to 50% silicon lithiation, 3% to 30% silicon lithiation, or 3% to 10% silicon lithiation. The minimum threshold level is the lithiation level below which the battery's cycle life decreases. The electrolyte includes liquid, solid, or gel.

Description

[Technical Field]

[0001] Cross-referencing / incorporation by reference of related applications This application claims priority to U.S. Patent Application No. 16 / 584,574, filed on 26 September 2019, entitled “Method and System for Silicon-Based Lithitated Silicon Lithium-Ion Cells,” the contents of which are incorporated herein by reference.

[0002] Aspects of this disclosure relate to energy generation and storage. More specifically, certain embodiments of this disclosure relate to methods and systems for silicon-based lithium-ion cells in which silicon lithiation is controlled. [Background technology]

[0003] Traditional approaches to battery anodes are costly, cumbersome, and / or inefficient; for example, they are complex and / or time-consuming to implement and can limit battery life.

[0004] Further limitations and disadvantages of conventional approaches will become apparent to those skilled in the art by comparing such systems with some aspects of the disclosure described in subsequent parts of this application, with reference to the drawings. [Overview of the Initiative] [Means for solving the problem]

[0005] A system and / or method for a silicon-based lithium-ion cell with controlled silicon lithiation, as fully described in the claims and substantially shown in and / or described in relation to at least one drawing.

[0006] Details of these and other advantages, aspects and novel features of the present disclosure, as well as the exemplary embodiments thereof, will be better understood from the following description and drawings. [Brief explanation of the drawing]

[0007] [Figure 1] FIG. 1 is a diagram of a battery comprising a silicon-based anode, according to an exemplary embodiment of the present disclosure. [Figure 2] illustrates an exemplary lithiation and delithiation process of a silicon-based anode, according to an exemplary embodiment of the present disclosure. [Figure 3] shows voltage profile curves of a lithium ion battery comprising a silicon-based anode, according to an exemplary embodiment of the present disclosure. [Figure 4] illustrates an exemplary lithiation and delithiation process of a prelithiated silicon-based anode, according to an exemplary embodiment of the present disclosure. [Figure 5] shows voltage profile curves of a lithium ion battery comprising a prelithiated silicon-based anode, according to an exemplary embodiment of the present disclosure. [Figure 6] illustrates a process for producing a prelithiated silicon anode, according to an exemplary embodiment of the present disclosure. [Figure 7] shows the fast charging capability of a cell comprising a silicon-based anode, according to an exemplary embodiment of the present disclosure. [Figure 8] is a plot showing cell cycle life versus charging rate for a silicon-based anode cell, according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF EMBODIMENTS

[0008] FIG. 1 is a diagram of a battery comprising a silicon-based anode according to an exemplary embodiment of the present disclosure. Referring to FIG. 1, there is shown a battery 100 comprising a separator 103 sandwiched between an anode 101 provided with current collectors 107A and 107B and a cathode 105. A load 109 coupled to the battery 100 is also shown, illustrating an example when the battery 100 is in a discharge mode. In the present disclosure, the term "battery" may be used to refer to a single electrochemical cell, a plurality of electrochemical cells formed into a module, and / or a plurality of modules formed into a pack.

[0009] The development of portable electronic devices and the electrification of transportation have driven the demand for high-performance electrochemical energy storage. Lithium-ion (Li-ion) batteries are mainly used in devices ranging from small-scale (<100Wh) to large-scale (>10KWh) because they have higher performance than other rechargeable batteries.

[0010] The anode 101 and the cathode 105, together with current collectors 107A and 107B, may constitute an electrode assembly. The electrodes may be located within an electrolyte material, or may include a plate or film comprising the electrolyte material. The plate may provide a physical barrier for containing the electrolyte and a conductive contact to an external structure. In other embodiments, the anode / cathode plates are immersed in the electrolyte, while an outer casing provides a containment vessel for the electrolyte. The anode 101 and the cathode are electrically coupled to the current collectors 107A and 107B, which comprise metal or other conductive materials to provide electrical contact to the electrodes and physical support for the active material during formation of the electrodes.

[0011] The configuration shown in Figure 1 shows the battery 100 in discharge mode, but in a charging configuration, the load 107 can be replaced with a charger to reverse the process. In one classification of batteries, the separator 101 is generally a film material made of an electrically insulating polymer, for example, it is sufficiently porous to allow ions to pass through while preventing electrons from flowing from the anode 101 to the cathode 105 and vice versa. Typically, the materials of the separator 103, the cathode 105, and the anode 101 are individually formed into sheets, films, or foils coated with active materials. Subsequently, the cathode, separator and anode sheets are stacked or wound together with the separator 103 separating the cathode 105 and the anode 101 to form the battery 100. In some embodiments, the separator 103 is a sheet, and winding methods and lamination are generally utilized in the manufacture thereof. In these methods, the anode, cathode, and current collector (e.g., electrodes) may comprise films.

[0012] In exemplary scenarios, battery 100 may contain a solid, liquid, or gel electrolyte. The separator 103 is preferably insoluble in typical battery electrolytes, such as compositions containing ethylene carbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), etc., with dissolved LiBF4, LiAsF6, LiPF6, and LiClO4. The separator 103 may be moistened or immersed in the liquid or gel electrolyte. Furthermore, in exemplary embodiments, the separator 103 does not melt below about 100 to 120°C and exhibits sufficient mechanical properties for battery applications. A battery in operation may experience expansion and contraction of the anode and / or cathode. In exemplary embodiments, the separator 103 can expand and contract by at least about 5 to 10% without failure and may also be flexible.

[0013] The separator 103 may be sufficiently porous, for example, to allow ions to pass through it when wetted with a liquid or gel electrolyte. Alternatively (or additionally), the separator may absorb the electrolyte through gelation or other processes even without significant porosity. The porosity of the separator 103 is also generally not sufficient to allow the anode 101 and cathode 105 to transfer electrons through the separator 103.

[0014] The anode 101 and cathode 105 comprise the electrodes of the battery 100 and provide electrical connections to devices for transferring charge during charging and discharging. The anode 101 may include, for example, silicon, carbon, or a combination of these materials. Typical anode electrodes include a current collector such as a copper sheet and contain carbon material. Carbon is often used because it has excellent electrochemical properties and is also conductive. Anode electrodes currently used in rechargeable lithium-ion batteries typically have a specific capacity of about 200 milliampere-hours per gram. The theoretical energy density of graphite, an active material used in the anodes of many lithium-ion batteries, is 372 milliampere-hours per gram (mAh / g). In comparison, silicon has a high theoretical capacity of 4200 mAh / g. To increase the volumetric and gravimetric energy density of lithium-ion batteries, silicon can be used as the active material for the cathode or anode. A silicon anode may be formed from, for example, a silicon composite material containing more than 50% silicon.

[0015] In an exemplary scenario, the anode 101 and cathode 105 store ions used for charge separation, such as lithium. In this example, the electrolyte carries positively charged lithium ions from the anode 101 to the cathode 105 in discharge mode, as shown in Figure 1, for example, and acts in the reverse direction via the separator 105 in charge mode. The movement of lithium ions generates free electrons at the anode 101, which generate a charge at the positive current collector 107B. Current then flows from the current collector through the load 109 to the negative current collector 107A. The separator 103 blocks the flow of electrons inside the battery 100.

[0016] While the battery 100 is discharging and supplying current, the anode 101 releases lithium ions to the cathode 105 via the separator 103, generating a flow of electrons from one side to the other via the coupled load 109. When the battery is charging, the opposite occurs: lithium ions are released by the cathode 105 and received by the anode 101.

[0017] The materials selected for the anode 101 and cathode 105 are crucial to the reliability and energy density of the battery 100. The energy, power, cost, and safety of current lithium-ion batteries need to be improved to compete with internal combustion engine (ICE) technology and enable the widespread adoption of electric vehicles (EVs). Improved energy density, power density, and safety of lithium-ion batteries are achieved through the development of functionally non-flammable electrolytes with high voltage stability and interfacial compatibility with electrodes, high-capacity and high-voltage cathodes, and high-capacity anodes. Furthermore, materials with lower toxicity are beneficial as battery materials to reduce process costs and promote consumer safety.

[0018] State-of-the-art lithium-ion batteries typically employ graphite-based anodes as the lithium insertion material. However, silicon-based anodes offer improvements compared to graphite-based lithium-ion batteries. Silicon exhibits higher gravimetric capacity (3579 mAh / g compared to 372 mAh / g for graphite) and volumetric capacity (2194 mAh / L compared to 890 mAh / L for graphite). Furthermore, silicon-based anodes offer a voltage difference of approximately 0.3-0.4 V vs. Li / Li + Due to its low lithiumization / delithiation voltage plateau, it can maintain an open-circuit potential and avoid the formation of undesirable Li plating and dendrites. Although silicon exhibits excellent electrochemical activity, achieving a stable cycle life for silicon-based anodes is difficult due to the large volume change of silicon during lithiumization and delithiation. The silicon region may lose electrical contact with the anode because, in addition to its low electrical conductivity, the large volume change separates silicon from the surrounding material within the anode.

[0019] Furthermore, large volume changes in silicon degrade solid electrolyte interface (SEI) formation, which can lead to further electrical insulation and thus capacitance loss. The expansion and contraction of silicon particles during charge-discharge cycles cause them to pulverize, increasing their specific surface area. As the surface area of ​​silicon changes and increases during the cycle, the SEI is repeatedly decomposed and reformed. Therefore, during the cycle, the SEI continuously accumulates around the pulverized silicon regions, forming a thick electron and ionic insulating layer. This accumulated SEI increases the impedance of the electrodes, reduces the electrochemical reactivity of the electrodes, and adversely affects the cycle life.

[0020] Due to its high specific capacity, abundance, and low cost, silicon is a promising active material for lithium-ion anodes. However, large volume changes (>300% volume change) during lithiation and delithiation cause mechanical degradation of the electrode and unstable SEI, leading to electrode swelling and reduced cell cycle life. Silicon-based anodes perform best when the lithiation of the silicon anode is maintained within a specific range. To achieve such performance, cells can be designed according to the criteria shown in Figure 2, for example. Silicon materials have upper and lower limits on lithiation for the desired cell operation. Upper limit x H This corresponds to the maximum lithium content that silicon can accept without significantly affecting cycle life. Lower limit x L This corresponds to the minimum threshold level, i.e., the minimum residual lithium content that must remain in the silicon structure to maximize cycle life. If the lithiation level falls below this level, the cycle life decreases with each cycle. The stage of silicon that is fully lithified at room temperature is Li 3.75 It is Si, which corresponds to the maximum theoretical capacity of silicon, 3579 mAh / g, and is much higher than the maximum theoretical capacity of graphite (372 mAh / g).

[0021] The cell receives the maximum amount of lithium x from the cathode. C x H It can be designed so as not to exceed this. Similarly, the minimum amount of lithium remaining in the anode after discharge (xD ) is x L must be higher than. The present disclosure describes a cell design in which silicon is partially pre-lithiated and then lithiated / delithiated during operation to achieve the target cell capacity and energy. Pre-lithiation means that lithium is incorporated into silicon during the manufacture of the anode, in contrast to the lithiation / delithiation that occurs during charging and discharging of the battery, and this pre-lithiation is not delithiated during discharging.

[0022] Figure 2 illustrates an exemplary lithiation and delithiation process for a silicon-based anode according to an exemplary embodiment of the present disclosure. Referring to Figure 2, the lithiation levels of a cathode and a silicon-based anode are shown. The lithiation level of the cathode represents the amount Δ that can migrate to the anode during the charging process Li , and the lithiation level of the anode increases from x D to x C . The lithiation level of the anode is shown on a scale from 0 to 3.75, where 3.75 represents the fully lithiated phase of silicon, Li 3.75 Si. The amount Δ Li may be a function of the number of charge carriers in the cathode and the cathode discharge cut-off voltage. Therefore, in this example, the lithiation of the anode is controlled by the cut-off voltage, and to obtain the best cycle life, it needs to be maintained at x L or higher. The discharged lithiation level x D is a function of the irreversible charges Q irr,アノード and Q irr,カソード of the anode and the cathode, as well as the cut-off voltage, and the charged lithiation level x C is a function of the number of charges in the material.

[0023] Figure 3 shows a voltage profile curve of a lithium-ion battery comprising a silicon-based anode according to an exemplary embodiment of the present disclosure. Referring to Figure 3, there are shown the voltage profile curves of the anode and the cathode, a vertical line marked with an arrow indicating the full cell voltage, and the ampere-hour cell capacity on the x-axis for these various full cell voltages.

[0024] In this example, the total charging capacity of the cathode is half the total capacity of the anode. During discharge, the cell voltage is such that, as explained with respect to Figure 2, the amount of lithium remaining in the anode is equal to the critical amount x L It can be controlled to be higher than that. For this particular cell, the cell capacity at 2.7V is 5.963mAh, the cell capacity at 3.1V is 4.555mAh, which is 76.4% of the total capacity, the cell capacity at 3.2V is 3.638mAh, which is 61.0% of the total capacity, and the cell capacity at 3.3V is 3.136mAh, which is 52.6% of the total capacity.

[0025] Figure 4 shows an exemplary lithiation and delithiation process of a pre-lithified silicon-based anode according to an exemplary embodiment of the present disclosure. Referring to Figure 4, the lithiation level range of cathode 401 and silicon-based anode 403 is shown. This example does not require limiting the cell voltage during discharge and the amount of lithium remaining in the anode after discharge (x D This shows another way to control ). This involves pre-lithifying the anode or regardless of the cell's discharge voltage x D x L To achieve a state higher than that, a cathode with a sufficiently high irreversible capacity is used. As previously mentioned, the anode lithiumization level is shown on a scale from 0 to 3.75, where 3.75 is the fully lithiumized stage of silicon. 3.75 This indicates Si.

[0026] The lithiumization level of the cathode in Figure 4 is the amount Δ that can be transferred to the anode 403 during the charging process described in Figure 2. Li Although 405 is shown, in this example the silicon anode is pre-lithified as shown 407, and as a result of pre-lithification, the lithiumization level is x regardless of the cutoff voltage used. L It is guaranteed to exceed x. In this example, pre-lithiation ensures that x L and x HThis allows for maximum utilization of cathode capacity while remaining within the limits.

[0027] Figure 5 shows voltage profile curves of a lithium-ion battery with a pre-lithified silicon-based anode according to an exemplary embodiment of the present disclosure. Referring to Figure 5, the anode and cathode voltage profile curves, a vertical line with an arrow indicating the full cell voltage, and the ampere-hour cell capacity on the x-axis at various full cell voltages are shown. Furthermore, (1) "lost" lithium, (2) "active" lithium or lithium storage, and (3) pre-lithification are shown.

[0028] Compared to the anode without pre-lithiation in Figure 3, pre-lithiation of the anode (3) extends the anode voltage curve to a higher capacity with a peak of 11 mAh. In this particular cell with 20% pre-lithiation, the cell capacity is 6.297 mAh at 2.7 V, 5.793 mAh at 3.1 V (92% of the total capacity), 5.000 mAh at 3.2 V (79.4% of the total capacity), and 3.306 mAh at 3.3 V (52.5% of the total capacity), showing a significant improvement over the unpre-lithified cell.

[0029] Furthermore, in addition to the improved cell capacity, pre-lithiation further enables: 1) controlled expansion and contraction of silicon during the charge and discharge cycles of the lithium-ion cell, thereby minimizing cracking, shattering, and SEI growth of silicon particles; 2) reduced cell capacity degradation during cycle lifetime due to controlled silicon expansion / contraction and the voltage window of the silicon anode; 3) maximization of cathode capacity utilization of lithium-ion cells using silicon as the anode material while maintaining a good cycle lifetime and limited cell expansion; and 4) rapid charging is possible because silicon is used within the range where it cannot be overlithiated, minimizing stress on the particles, thereby enabling high-rate charging and cycling of the cell, as explained with respect to Figures 7 and 8.

[0030] Figure 6 shows a pre-lithified silicon anode process according to an exemplary embodiment of the present disclosure. As shown in Figure 6, the process begins with step 601, in which, for example, a silicon-based anode can be pre-lithified to a lithiumization level between 3% and 95%. A battery or cell may be formed in step 603 with the pre-lithified silicon anode, cathode, and electrolyte.

[0031] In step 605, to avoid adversely affecting the battery cycle life, the lithium level is set to x C Until it reaches (x H The battery can be charged so that the anode is lithified by lithium from the cathode (while being kept below Δ). As previously explained with respect to Figure 4, the total amount of lithium moving is Δ Li It is possible. In the first example, x C The range is from 1.125 to 3.5625, which corresponds to 30% to 95% silicon lithiation, and 3.75 is the maximum silicon lithiation. In the second example, x C The range is from 1.125 to 3.1875, which corresponds to 30% to 85% lithium siliconization. In the third example, x C The range is from 1.125 to 2.8125, which corresponds to 30% to 75% lithium siliconization. In the fourth example, x C The range is from 1.125 to 2.4375, which corresponds to 30% to 65% lithium siliconization. In the fifth example, x C The range is from 1.125 to 1.875, which corresponds to 30% to 50% lithium silicon.

[0032] In step 607, the battery's anode is x due to pre-lithiation. L Maintaining a higher level x D It can be delithified to the point where lithium returns to the cathode and then discharged. In the first example, x D The range is from 0.12 to 1.875, which corresponds to 3% to 50% residual lithium in silicon. In the second example, x DThe range is from 0.12 to 1.5, which corresponds to 3% to 40% residual lithium in silicon. In the third example, x D The range is from 0.12 to 1.125, which corresponds to 3% to 30% residual lithium in silicon. In the fourth example, x D The range is from 0.12 to 0.75, which corresponds to 3% to 20% residual lithium in silicon. In the first example, x D The range is from 0.12 to 0.375, which corresponds to 3% to 10% residual lithium in silicon.

[0033] In step 609, if the cell voltage is still acceptable, i.e., the cell is not at the end of its cycle life, the process may return to step 605 to charge and discharge again.

[0034] Figure 7 shows the fast charging capability of a cell with a silicon-based anode according to an exemplary embodiment of the present disclosure. Refer to Figure 1. Referring to Figure 7, the charging curves of a cell with a conventional graphite anode and the charging curves of a cell with a pre-lithified silicon-based anode at charging rates of 4C, 5.6C, and 10C are shown. As shown in the plot, the silicon-based anode cell can be charged at very high rates. Thus, the level of silicon lithiumization is controlled by the cell design and / or the best use of the silicon anode. Lithium storage is required to obtain the best performance of the cell, and storage can be formed by utilizing the cathode in the manner described with respect to Figures 2 and 3, or through pre-lithization as described with respect to Figures 4 and 5.

[0035] Figure 8 is a plot showing the cell cycle lifetime versus charge rate of a silicon-based anode cell according to an exemplary embodiment of the present disclosure. As shown by the plots which lie nearly collinear, there is no essential difference in cell lifetime between a cell charged at 0.5C and a cell charged at a 4C rate. Both cells maintain 92% of their capacity up to 500 cycles.

[0036] Exemplary embodiments of this disclosure describe methods and systems for silicon-based lithium-ion cells with controlled silicon lithiation. The cell may include a cathode, an electrolyte, and an anode. The anode may contain silicon lithified to a post-discharge level configured to exceed a minimum threshold level, the minimum threshold of lithiation being 3% silicon lithiation. The post-discharge silicon lithiation level may be configured by the discharge voltage of the anode. The post-discharge silicon lithiation level may be configured by the pre-lithiation level of silicon. The post-discharge silicon lithiation level may be configured by the irreversible discharge capacity of the cathode. The silicon lithiation level after charging the cell may range from 30% to 95% silicon lithiation, 30% to 75% silicon lithiation, 30% to 65% silicon lithiation, or 30% to 50% silicon lithiation. The lithiumization level of silicon after battery discharge can range from 3% to 50% silicon lithiumization, 3% to 30% silicon lithiumization, or 3% to 10% silicon lithiumization. A minimum threshold level may be the lithiumization level below which the battery's cycle life decreases. The electrolyte may include liquid, solid, or gel forms.

[0037] In another exemplary embodiment, a method and system for an anode used in a battery is described, the anode comprising silicon which, when incorporated into a lithium-ion battery, is lithified beyond a minimum threshold level during discharge, the post-discharge lithification level of silicon being determined by the anode's discharge voltage or the pre-lithification level of silicon.

[0038] As used herein, the term “circuit” means physical electronic components (i.e., hardware), as well as software and / or firmware (”code”) that constitute the hardware, are executed by the hardware, and / or otherwise may be associated with the hardware. As used herein, for example, a particular processor and memory may include a first “circuit” if it executes a first line or more of code, and a second “circuit” if it executes a second line or more of code. As used herein, “and / or” means any one or more items in the list linked by “and / or”. For example, “x and / or y” means any element of the set of three elements {(x), (y), (x, y)}. In other words, “x and / or y” means “either x or y or both of x and y”. As another example, “x, y, and / or z” means any element of the set of seven elements {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, “x, y, and / or z” means “one or more of x, y, and z.” As used herein, the term “exemplary” means to serve as an unrestricted example, example, or illustration. As used herein, the term “for example” indicates a list of one or more unrestricted examples, examples, or illustrations. As used herein, a circuit or device is “operable” to perform a function, regardless of whether the performance of the function is disabled or enabled (e.g., by user-configurable settings, factory adjustments, etc.), as long as it contains the hardware and code (if necessary) required for the circuit or device to perform the function.

[0039] Although the present invention has been described with reference to specific embodiments, those skilled in the art will understand that various modifications can be made and equivalents can be substituted without departing from the scope of the invention. Furthermore, many modifications can be made without departing from the scope to adapt the teachings of the invention to specific situations or materials. Thus, the present invention is not limited to the specific embodiments disclosed, and is intended to include all embodiments contained within the appended claims.

Claims

1. A battery comprising a cathode, an electrolyte, and an anode, The anode comprises silicon lithified to a level configured to exceed a minimum threshold level after discharge, The minimum threshold for lithiumization is 3% silicon lithiumization in a battery.

2. The battery according to claim 1, wherein the lithiumization level of silicon after discharge is determined by the discharge voltage of the anode.

3. The battery according to claim 1, wherein the lithiumization level of silicon after discharge is guaranteed to exceed a minimum threshold level due to the pre-lithiation of silicon.

4. The battery according to claim 1, wherein the lithiumization level of silicon after discharge is determined by the irreversible discharge capacity of the cathode.

5. The battery according to claim 1, wherein the lithiumization level of silicon after charging of the battery is in the range of 30% to 95% silicon lithiumization.

6. The battery according to claim 1, wherein the lithiumization level of silicon after charging of the battery is in the range of 30% to 75% silicon lithiumization.

7. The battery according to claim 1, wherein the lithiumization level of silicon after charging of the battery is in the range of 30% to 65% silicon lithiumization.

8. The battery according to claim 1, wherein the lithiumization level of silicon after charging of the battery is in the range of 30% to 50% silicon lithiumization.

9. The battery according to claim 1, wherein the lithiumization level of silicon after discharge of the battery is in the range of 3% to 50% silicon lithiumization.

10. The battery according to claim 1, wherein the lithiumization level of silicon after discharge of the battery is in the range of 3% to 30% silicon lithiumization.

11. The battery according to claim 1, wherein the lithiumization level of silicon after discharge of the battery is in the range of 3% to 10% silicon lithiumization.

12. The battery according to claim 1, wherein the minimum threshold level is a lithiumization level below which the battery's cycle life decreases.

13. The battery according to claim 1, wherein the electrolyte comprises a liquid, a solid, or a gel.

14. A step of forming a battery comprising an anode, a cathode, and an electrolyte, wherein the anode comprises silicon. The steps include charging the battery so that the anode is lithium-ionized, A step of discharging the battery, wherein the lithiumization level of the anode remains above a minimum threshold level after discharge, and the minimum threshold lithiumization is 3% silicon lithiumization. Methods that include...

15. The method according to claim 14, further comprising the step of determining the lithiumization level of silicon after discharge by the discharge voltage of the anode.

16. The method according to claim 14, comprising the step of ensuring that the lithiumization level of silicon after discharge exceeds a minimum threshold level by utilizing the pre-lithiation of silicon.

17. The method according to claim 14, further comprising the step of determining the lithiumization level of silicon after discharge by the irreversible discharge capacity of the cathode.

18. The method according to claim 14, wherein the lithiumization level of silicon after charging the battery is in the range of 30% to 95% silicon lithiumization.

19. The method according to claim 14, wherein the lithiumization level of silicon after charging the battery is in the range of 30% to 75% silicon lithiumization.

20. The method according to claim 14, wherein the lithiumization level of silicon after charging the battery is in the range of 30% to 65% silicon lithiumization.

21. The method according to claim 14, wherein the lithiumization level of silicon after charging the battery is in the range of 30% to 50% silicon lithiumization.

22. The method according to claim 14, wherein the lithiumization level of silicon after the discharge of the battery is in the range of 3% to 50% silicon lithiumization.

23. The method according to claim 14, wherein the lithiumization level of silicon after the discharge of the battery is in the range of 3% to 30% silicon lithiumization.

24. The method according to claim 14, wherein the lithiumization level of silicon after the discharge of the battery is in the range of 3% to 10% silicon lithiumization.

25. The method according to claim 14, wherein the minimum threshold level is a lithiumization level below which the battery cycle life decreases.

26. An anode for use in a battery, wherein the anode, when incorporated into a lithium-ion battery, contains silicon that is lithified beyond a minimum threshold level during discharge, and the lithiumization level of the silicon after discharge is determined by the discharge voltage of the anode or by the pre-lithization level of the silicon.

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