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

Abstract

The present invention provides a system and / or method for silicon-based lithium-ion cells in which the utilization of silicon is controlled. [Solution] A system and method for a silicon-based lithium-ion cell with controlled silicon utilization may include a cathode, an electrolyte, and an anode, the anode having an active material containing more than 50% silicon. The battery may be charged by lithiumizing silicon without lithiumizing carbon. The active material may contain more than 70% silicon. The voltage of the anode during battery discharge may be maintained higher than the minimum voltage at which silicon can be lithiumized. The anode may have a specific capacity of more than 3000 mAh / g. The battery may have a specific capacity of more than 1000 mAh / g. The anode has an initial Coulomb efficiency of more than 90% and does not need to contain a polymer binder. The battery may be charged at a rate of 10C or higher. The battery may be charged at sub-zero temperatures without forming lithium plating. The electrolyte may include a 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 / 594,508, filed on 7 October 2019, the contents of which are incorporated herein by reference in their entirety.

[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 with controlled silicon utilization. [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 utilization, 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] This is a diagram of a lithium-ion battery according to an exemplary embodiment of the present disclosure. [Figure 2] The voltages of the anode, cathode, and cell during charging of a lithium-ion cell are shown according to exemplary embodiments of the present disclosure. [Figure 3] An exemplary embodiment of the present disclosure shows a lithium-ion cell with lithium plating and dendrites formed thereon. [Figure 4] The voltage levels during charging of a silicon-doped graphite anode according to exemplary embodiments of the present disclosure are shown. [Figure 5] The present disclosure illustrates the mechanical processes between the lithiation and delithiation of silicon-doped anodes and silicon film anodes according to exemplary embodiments of this disclosure. [Figure 6] The voltage levels during charging of the silicon film anode according to exemplary embodiments of the present disclosure are shown. [Figure 7] The first cycle voltage curve of a half-cell silicon-based anode according to an exemplary embodiment of the present disclosure is shown. [Figure 8] The electrode voltage and cell voltage of a cell equipped with a silicon-based anode according to exemplary embodiments of the present disclosure are shown. [Figure 9] The charge rates of silicon-based cells and graphite cells according to exemplary embodiments of this disclosure are shown. [Figure 10] The charging time of a silicon-based cell at low temperatures according to exemplary embodiments of this disclosure is shown. [Figure 11] The capacity retention rate of silicon-based cells with respect to charging temperature according to exemplary embodiments of this disclosure is shown. [Figure 12] Examples of lithiation and delithiation processes of silicon-based anodes according to exemplary embodiments of the present disclosure are shown. [Figure 13] The voltage curve of a lithium-ion battery with a silicon-based anode according to an exemplary embodiment of the present disclosure is shown. [Figure 14] This disclosure illustrates a process using a silicon-based anode cell according to an exemplary embodiment of the present disclosure. [Modes for carrying out the invention]

[0008] Figure 1 is a diagram of a lithium-ion battery according to an exemplary embodiment of the present disclosure. Referring to Figure 1, a battery 100 is shown, which includes a separator 103 sandwiched between an anode 101 and a cathode 105, with current collectors 107A and 107B. A load 109 coupled to the battery 100 is also shown, illustrating an example of the battery 100 in discharge mode. In this disclosure, the term “battery” may be used to refer to a single electrochemical cell, a plurality of electrochemical cells formed in a module, and / or a plurality of modules formed in a pack.

[0009] The development of portable electronic devices and the electrification of transportation are driving the need for high-performance electrochemical energy storage. Small-scale (<100Wh) to large-scale (>10kWh) devices primarily use lithium-ion (Li-ion) batteries rather than other rechargeable batteries due to their high performance.

[0010] The anode 101 and cathode 105, together with the current collectors 107A and 107B, may include electrodes, which may be contained within an electrolyte material or include a plate or membrane containing the electrolyte material, and the plate may provide a physical barrier for containing the electrolyte and conductive contacts to an external structure. In other embodiments, the anode / cathode plate is immersed in the electrolyte, while the outer casing provides a container for the electrolyte. The anode 101 and cathode are electrically coupled to the current collectors 107A and 107B, which include metal or other conductive material to provide electrical contact to the electrodes and physical support for the active material when forming the electrodes.

[0011] The configuration shown in FIG. 1 shows the battery 100 in the discharge mode. In the charging configuration, the load 107 can be replaced with a charger to reverse the process. In one classification of batteries, the separator 103 is generally a membrane material made of an electrically insulating polymer. For example, it has sufficient porosity for ions to pass through while preventing electrons from flowing from the anode 101 to the cathode 105 or vice versa. Typically, the materials of the separator 103, the cathode 105, and the anode 101 are individually formed into sheets, membranes, or foils coated with an active material. Subsequently, the sheets of the cathode, separator, and anode are laminated 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 typically, in its manufacture, winding methods and lamination are utilized. In these methods, the anode, cathode, and current collector (e.g., electrode) may include a membrane.

[0012] In an exemplary scenario, the battery 100 may include a solid, liquid, or gel electrolyte. The separator 103 is preferably insoluble in typical battery electrolytes such as compositions that may include ethylene carbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), etc. in which LiBF4, LiAsF6, LiPF6, and LiClO4 are dissolved. The separator 103 can be wetted or immersed in a liquid or gel electrolyte. Further, in an exemplary embodiment, the separator 103 does not melt below about 100 to less than 120 °C and exhibits sufficient mechanical properties for battery applications. The operating battery may experience expansion and contraction of the anode and / or cathode. In an exemplary embodiment, the separator 103 can expand and contract by at least about 5 to 10% without failure and may also have flexibility.

[0013] Separator 103 can be sufficiently porous, for example, such that ions can pass through the separator when wetted with a liquid or gel electrolyte. Alternatively (or additionally), the separator can absorb the electrolyte through a gelling or other process, even without significant porosity. The porosity of separator 103 is also generally not so porous as to allow anode 101 and cathode 105 to transfer electrons through separator 103.

[0014] Anode 101 and cathode 105 include the electrodes of battery 100 and provide an electrical connection to a device for transferring charge in the charged and discharged states. Anode 101 can include, for example, silicon, carbon, or a combination of these materials. A typical anode electrode includes a current collector such as a copper sheet and includes a carbon material. Carbon is often used because it has excellent electrochemical properties and conductivity. The 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, which is the 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 of the cathode or anode. A silicon anode can be formed, for example, from a silicon composite material containing more than 50% silicon. In another example, the anode can contain more than 70% silicon and can include a self-standing monolithic single-particle film without a binder material.

[0015] 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 anode 101 to cathode 105 in discharge mode, as shown in Figure 1, and in reverse in charge mode via separator 105. The movement of lithium ions generates free electrons at anode 101, which generate a charge at positive current collector 107B. Current then flows from the current collector through load 109 to negative current collector 107A. 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 for 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 high energy density, high 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] Current 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 + Because it has a low lithium / delithiation voltage plateau, as shown in Figure 3, the open-circuit potential can be maintained, avoiding the formation of undesirable Li plating and dendrites.

[0019] Although silicon exhibits excellent electrochemical activity, achieving a stable cycle life for silicon-based anodes is difficult due to the large volume changes of silicon during lithiation and delithiation. The silicon region, in addition to its low electrical conductivity, can lose electrical contact with the anode because the large volume changes separate the silicon from the surrounding material within the anode.

[0020] 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. Thus, during the cycle, the SEI continuously accumulates around the pulverized silicon regions, forming a thick electron and ion insulating layer. This accumulated SEI increases the impedance of the electrodes, reduces the electrochemical reactivity of the electrodes, and adversely affects the cycle life.

[0021] Figure 2 shows the anode, cathode, and cell voltages during charging of a lithium-ion battery according to an exemplary embodiment of the present disclosure. Referring to Figure 2, the voltage of a lithium-ion cell over time during charging is shown. As the cell charges, the cathode voltage rises to supply lithium to the anode, and as lithium is lithified, the anode voltage decreases, resulting in an increase in the cell voltage.

[0022] In conventional graphite anodes, when the anode voltage drops to a level where the graphite is lithium-plated, lithium plating inevitably occurs, reducing the cell's capacity and causing safety problems due to dendrites that form over time, ultimately short-circuiting the cell as shown in Figure 3.

[0023] Figure 3 shows a lithium-ion cell with lithium plating and dendrites formed according to an exemplary embodiment of the present disclosure. Referring to Figure 3, a battery 300 is shown comprising an anode 310, a separator 303, and a cathode 305. In this example, the anode contains a graphite active material in which, over time, a low anode voltage causes lithium plating and dendrite formation. Dendrites extending through the separator 303 can cause catastrophic failure of the lithium-ion cell and potentially cause a fire. This effect can be eliminated by using a silicon-based anode in which the active material contains little to no graphite, and by configuring the discharge voltage to drop only to a level where silicon is lithified, i.e., not to reach a voltage low enough to lithify the graphite in the cell.

[0024] Figure 4 shows the voltage levels during charging of a silicon-doped graphite anode according to an exemplary embodiment of the present disclosure. Referring to Figure 4, three different voltage stages of silicon and graphite anodes are shown. The upper stage shows the anode voltage when the cell is completely discharged and the anode voltage is at its highest level, higher than the voltage at which silicon or graphite lithium is produced. At this stage, the anode is delithitated.

[0025] The second stage shows an intermediate voltage where the cell is charging, the graphite has not yet reacted, but the silicon is lithium-ionized. In the case of a silicon-doped graphite anode, the cell is charged further to a third stage because the graphite needs to be lithium-ionized to obtain the full cell capacity. In the third stage, the cell continues to charge until the anode voltage is low enough that the silicon is completely lithium-ionized and the graphite is lithium-ionized. The voltage continues to decrease as the graphite is lithium-ionized, so as mentioned earlier, the voltage drops to the level where plating occurs and dendrites are formed.

[0026] Figures 5A and 5B illustrate the mechanical processes between lithiation and delithiation of silicon-doped anodes and silicon film anodes according to exemplary embodiments of the present disclosure. Referring to Figure 5A, the expansion and contraction of the active material of the anode are shown, and the active material comprises silicon-doped graphite. The first figure is before lithiation, the second is after lithiation, and the third is after delithiation.

[0027] In such conventional silicon-containing anodes, the graphite and silicon materials are typically held together by a soft polymer binder, allowing for expansion of the material during lithiation, which is a normal process by silicon during lithiation. Since silicon is highly or completely lithified, the graphite anode active material can be sufficiently lithified to allow for full cell capacity, as shown in Figure 4. The expansion of fully lithified silicon is approximately 300-400% in silicon-doped graphite anodes, leading to significant deformation or failure of the binder. Furthermore, when the active material is delithified, the silicon shrinks, generating tensile stress, which can cause the polymer holding the electrodes together to break and crack in the material.

[0028] The silicon film anode shown in Figure 5B is held together by a strong conductive matrix and does not utilize graphite as an active material. Therefore, compared to silicon-graphite anodes, a smaller proportion of silicon can be used during lithiation, resulting in reduced swelling. Furthermore, the nanocoating of the electrode material prevents side reactions. Consequently, due to reduced expansion and a strong conductive matrix, silicon-based anodes do not suffer from the problems associated with silicon-graphite anodes.

[0029] Figure 6 shows the voltage levels during charging of a silicon film anode according to an exemplary embodiment of the present disclosure. Referring to Figure 6, two different voltage stages of a silicon-based anode are shown. Since the anode active material contains little to no graphite, there is no graphite lithiation, and therefore the carbon lithiation voltage is not shown here. The upper row shows the anode voltage when the cell is fully discharged and the anode voltage is at its highest level, higher than the silicon lithiation voltage. At this stage, the anode is delithitated. As the anode is charged, the voltage decreases as silicon is lithitated, and since the anode uses only silicon for lithiation and not all silicon is lithitated to a full charge, the cell is fully charged when the voltage enters the silicon lithiation voltage range. That is, the voltage does not drop below the lower limit of the silicon lithiation voltage range. Since the anode voltage never falls below the silicon lithiation voltage, carbon is hardly lithitated, and lithium plating can be essentially eliminated. For example, under normal operation, less than 10% of the carbon may be lithitated. In another example, under normal operation, less than 20% of the carbon is lithium-ionized. Furthermore, since a smaller portion of the silicon is lithium-ionized, the swelling described above is reduced.

[0030] Figure 7 shows the first cycle voltage profile of an anode half-cell for an exemplary silicon-based anode. In this case, the initial lithium-ion voltage curve is lower than that seen during normal operation because it is the first charge. Referring to Figure 7, the voltage profile of the silicon-based anode is shown, indicating an initial charge capacity of approximately 3000 mAh / g, an irreversible capacity of approximately 250 mAh / g, and a resulting initial Coulomb efficiency of 92%. In this initial charge process, the anode was charged at a C / 16 rate, and the anode voltage ranged from 0.01V to 1.2V.

[0031] In an exemplary embodiment, a silicon film anode containing more than 70% silicon achieves a specific capacity of approximately 3000 mAh / g (compared to a maximum of 372 mAh / g for graphite), 1000-2000 mAh / g when used in a cell, with a maximum volumetric energy density of 2000 Wh / L and a maximum gravimetric energy density of 350 Wh / kg.

[0032] Figure 8 shows the electrode and cell voltages of a cell with a silicon-based anode according to an exemplary embodiment of the present disclosure. Referring to Figure 8, the anode voltage, cathode voltage, and cell voltage against the time of the charge and discharge cycles are shown. The left half of the plot shows the charging of the cell, with the cell voltage reaching a maximum of 4.2V at 45,000 seconds, which is the C / 10 charge rate for this example cell. Due to the charging process, the anode voltage drops to approximately 0.1V. During the normal operation of such a cell, the high specific capacitance of silicon in the anode keeps the anode voltage within a range that does not utilize the full range of the anode, effectively eliminating the lithium plating problem by avoiding complete delithiation of silicon, which would lead to greater stress and potential cracking.

[0033] The right half of the plot shows the C / 10 discharge of the cell, where the cell voltage drops to approximately 3.4V. In this example scenario, the anode cycles between 0.1V and 0.5V, the cathode voltage is higher than that of the graphite cell, and the cell voltage slope is steeper than that of the cell containing both silicon and graphite.

[0034] Figure 9 shows the charge rates of silicon-based and graphite cells according to exemplary embodiments of the present disclosure. Referring to Figure 9, plots of the ratio of full charge to time are shown for cells with a silicon-doped graphite anode and silicon-based anode cells. As can be seen in the plot, the graphite cell is only 50% charged after 30 minutes, while the silicon-based anode cell reaches 75% charge in just 5 minutes when charged at a 10C rate. Even when charged at a 10C rate, the cell retains at least 50% of its 1C rate charge retention up to 80% of its original capacity.

[0035] These charging curves demonstrate the advantages of silicon-based anode cells, where, in addition to the lithiation of graphite, a smaller proportion of silicon in silicon-doped graphite cells is lithified / delithiated during use compared to cases where 100% of the small amount of silicon in silicon-doped graphite cells is lithified. Once the material reaches maximum lithiation, the rate at which the material can absorb more lithium decreases, so silicon-graphite cells need to be charged at a much slower rate. Because silicon has a much higher specific capacity and silicon-based anodes lithify only a portion of the silicon, the lithiation rate can be maintained at a high level until fully charged, resulting in a significantly faster cell charging speed.

[0036] Figure 10 shows the charging time of a silicon-based cell at low temperature according to an exemplary embodiment of the present disclosure. Referring to Figure 10, a plot of the percentage of time to full charge of a silicon-based anode cell at -20°C is shown. As can be seen in the plot, the cell reaches 75% charge within 30 minutes, which is slower than charging at room temperature, but is possible at least without causing lithium plating.

[0037] Figure 10 shows charging of silicon-based anode cells at -20°C, but does not show conventional silicon-graphite cells because they cannot be charged below 0°C (32°F). If attempted, the pack may appear to charge normally, but metallic lithium plating can form on the anode during sub-zero charging, which is permanent and cannot be removed by cycling. Because lithium plating is dangerous to the cell's operation, advanced chargers do not attempt to charge cells at sub-zero temperatures.

[0038] Figure 11 shows the capacity retention rates of a silicon-based cell at different charging temperatures according to exemplary embodiments of the present disclosure. Referring to Figure 11, the capacity retention rates of a silicon-based anode cell are shown, with the first bar representing the initial capacity at 100%, and the second bar representing the capacity after charging sequences of 0.3C, 0.7C, 1C, 2C, 3C, 5C, and 7C at 23°C. As can be seen from the figure, after this sequence, the cell's capacity has not decreased at all. The third bar represents the cell after the same charging sequence at -20°C. This demonstrates that the disclosed silicon-based anode cell not only can be charged below freezing point but also maintains its capacity, in contrast to silicon graphite anode cells, which develop lithium plating when attempted to be charged at sub-zero temperatures.

[0039] Figure 12 illustrates an exemplary lithium-ion and delithiation process of a silicon-based anode according to an exemplary embodiment of the present disclosure. Referring to Figure 12, the lithium-ion levels of the cathode and silicon-based anode are shown. The lithium-ion level of the cathode is the amount Δ that can move to the anode during the charging process. Li This indicates that the lithiumization level of the anode is x D from x C It rises. As can be seen from the range of anode capacity compared to cathode, a small proportion of lithium silicon capacity is used, which results in a very high charge rate as described above.

[0040] The anode lithiumization level is shown on a scale from 0 to 3.75, where 3.75 is the level of lithium where silicon is completely lithium. 3.75Shows Si. The quantity Δ Li can be a function of the number of charge carriers in the cathode and the cathode discharge cut-off voltage. Thus, in this example, the lithiation of the anode is controlled by the cut-off voltage and, to obtain the best cycle life, x L needs to be kept above. 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 , and the cut-off voltage, and the charged lithiation level x C is a function of the number of charges of the material.

[0041] Due to the large lithiation capacity of the silicon anode, the configuration of the anode voltage during discharge can exceed the voltage of the plating threshold by far. The example shown in FIG. 12 shows an anode lithiated only by the cathode, and the pre-lithiation of the anode can also be utilized to ensure that the lithiation level does not drop below x L .

[0042] FIG. 13 shows the voltage profile curve of a lithium-ion battery equipped with a silicon-based anode according to an exemplary embodiment of the present disclosure. Referring to FIG. 13, the voltage profile curves of the anode and the cathode, the vertical line with an arrow indicating the full cell voltage, and the cell capacity in ampere-hours on the x-axis of these various full cell voltages are shown.

[0043] In this example, the total charge capacity of the cathode is half of the total capacity of the anode. During discharge, the cell voltage can be controlled such that the amount of lithium remaining in the anode is higher than the critical amount x L . For this particular cell, the cell capacity at 2.7V is 5.963 mAh, the cell capacity at 3.1V is 4.555 mAh corresponding to 76.4% of the total capacity, the cell capacity at 3.2V is 3.638 mAh corresponding to 61.0% of the total capacity, and the cell capacity at 3.3V is 3.136 mAh corresponding to 52.6% of the total capacity.

[0044] As described above, this silicon-based anode configuration allows the anode voltage to remain sufficiently high above the voltage at which lithium plating occurs on the anode, significantly improving battery life. Furthermore, because the anode capacity is very high due to silicon, and the silicon utilization rate can be kept low, the possible charge rate is much higher than that of a silicon-graphite anode, and as mentioned earlier, low-temperature charging is also possible.

[0045] Figure 14 shows a silicon-based anode cell usage process according to an exemplary embodiment of the present disclosure. Referring to Figure 14, the process begins with step 1401, in which the silicon-based anode is assembled together with the cathode and electrolyte to form a battery / cell. In step 1403, the cell may be charged, lithonizing some of the silicon in the anode so that the silicon is not completely lithium-ionized, and configuring the anode voltage to be maintained above the minimum voltage for silicon lithium-ionization. In step 1405, the cell may be discharged, and in step 1407, if the cell voltage is still acceptable, i.e., if there is remaining cell life, the process repeats step 1403; otherwise, the cell terminates in step 1409.

[0046] Exemplary embodiments of this disclosure describe methods and systems for silicon-based lithium-ion cells with controlled silicon utilization. The battery may comprise a cathode, an electrolyte, and an anode, the anode having an active material containing more than 50% silicon. The battery may be charged by lithifying silicon without lithifying carbon (i.e., carbon is not lithified). The active material may contain more than 70% silicon. The voltage of the anode during battery discharge may be maintained above the minimum voltage at which silicon can be lithified. The anode may have a specific capacity greater than 3000 mAh / g. The battery may have a specific capacity greater than 1000 mAh / g. The anode may have an initial Coulomb efficiency greater than 90%. The anode active material may not contain a polymer binder. The battery may be operable to charge at a rate of 10C or higher while retaining at least 50% of the 1C rate storage capacity at 80% of the battery's initial capacity. The battery may be charged at sub-zero temperatures without forming a lithium plating. Electrolytes may include liquids, solids, or gels.

[0047] 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.

[0048] While 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 included in the appended claims.

[0049] The present invention may further include the following embodiments. [Section 1] A battery comprising a cathode, an electrolyte, and an anode having an active material containing more than 50% silicon, A battery that is charged by the lithiumization of silicon while less than 20% of the carbon in the active material is lithiumized. [Section 2] The battery according to item 1, wherein the active material contains more than 70% silicon. [Section 3] The battery according to claim 1, wherein the voltage of the anode during the discharge of the battery is maintained above the minimum voltage at which silicon can be lithium-ionized. [Section 4] The battery according to item 1, wherein the anode has a specific capacity exceeding 3000 mAh / g. [Section 5] The battery according to item 1, wherein the battery has a specific capacity exceeding 1000 mAh / g. [Section 6] The battery according to item 1, wherein the anode has an initial Coulomb efficiency of more than 90%. [Section 7] The battery according to item 1, wherein the anode active material does not contain a polymer binder. [Section 8] The battery according to item 1, wherein the battery is capable of being charged at a rate of 10C or higher while maintaining at least 50% of its storage capacity at a rate of 1C at 80% of its original capacity. [Section 9] The battery according to item 1, wherein the battery can be charged at sub-zero temperatures without forming lithium plating. [Section 10] The battery according to item 1, wherein the electrolyte comprises a liquid, a solid, or a gel. [Section 11] A method for forming a battery, comprising a cathode, an electrolyte, and an anode having an active material containing more than 50% silicon, the battery being charged by lithiumizing silicon while lithiumizing less than 20% of the carbon in the active material. [Section 12] The method according to item 11, wherein the active material contains more than 70% silicon. [Section 13] The method according to claim 11, comprising the step of configuring the voltage of the anode during the discharge of the battery to exceed the minimum voltage at which silicon can be lithium-ionized. [Section 14] The method according to item 11, wherein the anode has a specific capacity of more than 3000 mAh / g. [Section 15] The method according to item 11, wherein the battery has a specific capacity exceeding 1000 mAh / g. [Section 16] The method according to item 11, wherein the anode has an initial Coulomb efficiency of more than 90%. [Section 17] The method according to claim 11, wherein the anode active material does not contain a polymer binder. [Section 18] The method according to item 11, comprising the step of charging the battery at a rate of 10C or higher. [Section 19] The method according to claim 11, comprising the step of charging the battery at a sub-zero temperature without forming lithium plating. [Section 20] an anode for use in batteries, The anode contains an active material containing more than 50% silicon, An anode that is charged within a battery by lithium-ionizing silicon while lithium-ionizing less than 20% of the carbon in the active material. [Explanation of symbols]

[0050] 100, 300 batteries 101, 301 anodes 103, 303 Separator 105, 305 cathode 107A, 107B current collectors 109 load

Claims

1. A battery comprising a cathode, an electrolyte, and an anode having an active material containing more than 50% silicon, The silicon in the active material is charged by lithiumization while less than 20% of the carbon is lithiumized. The battery is a battery that is charged without forming lithium plating.

2. The battery according to claim 1, wherein the active material contains more than 70% silicon.

3. The battery according to claim 1, wherein the voltage of the anode during discharge of the battery is maintained above the minimum voltage at which silicon can be lithium-ionized.

4. The battery according to claim 1, wherein the anode has a specific capacity of more than 3000 mAh / g.

5. The battery according to claim 1, wherein the battery has a specific capacity of more than 1000 mAh / g.

6. The battery according to claim 1, wherein the anode has an initial Coulomb efficiency of more than 90%.

7. The battery according to claim 1, wherein the active material of the anode does not contain a polymer binder.

8. The battery according to claim 1, wherein the battery is operable to be charged at a rate of 10C or higher while maintaining at least 50% of its storage capacity at a rate of 1C at 80% of its initial capacity.

9. The battery according to claim 1, wherein the battery can be charged at sub-zero temperatures without forming lithium plating.

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

11. A battery comprising a cathode, an electrolyte, and an anode having an active material containing more than 50% silicon, comprising the step of charging the battery by lithiumizing silicon while lithiumizing less than 20% of the carbon in the active material, A method for forming a battery, comprising the step of charging the battery without forming lithium plating.

12. The method according to claim 11, wherein the active material contains more than 70% silicon.

13. The method according to claim 11, further comprising the step of configuring the voltage of the anode during the discharge of the battery to exceed the minimum voltage at which silicon can be lithium-ionized.

14. The method according to claim 11, wherein the anode has a specific capacity of more than 3,000 mAh / g.

15. The method according to claim 11, wherein the battery has a specific capacity of more than 1000 mAh / g.

16. The method according to claim 11, wherein the anode has an initial Coulomb efficiency of more than 90%.

17. The method according to claim 11, wherein the active material of the anode does not contain a polymer binder.

18. The method according to claim 11, further comprising the step of charging the battery at a rate of 10C or higher.

19. The method according to claim 11, further comprising the step of charging the battery at a sub-zero temperature without forming lithium plating.

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