Abstract: The present application relates to a battery module, including a first-type battery cell and a second-type battery cell electrically connected at least in series, the first-type battery cell and the second-type battery cell are battery cells of different chemical systems, the first-type battery cell includes N first battery cell(s), the second-type battery cell includes M second battery cell(s); the first battery cell includes a first negative electrode plate, the second battery cell includes a second negative electrode plate, a ratio of a conductivity of an electrolyte solution (25° C.) of the first battery cell to a coating mass per unit area of the first negative electrode plate is denoted as M1, and a ratio of a conductivity of an electrolyte solution (25° C.) of the second battery cell to a coating mass per unit area of the second negative electrode plate is denoted as M2, M1>M2, and 0.08?M1?11, 0.03?M2?4.62.

Abstract: A charging method for an electrochemical device includes the following steps: in a first cycle stage, a charging stage of the first cycle stage has a first cut-off current; and in a second cycle stage, a charging stage of the second cycle stage has a second cut-off current, and the second cut-off current is greater than the first cut-off current. According to the charging method for an electrochemical device, an electronic device, and a readable storage medium provided in the present application, the risk of cyclic gas generation of the electrochemical device can be effectively prevented, and the service life of the electrochemical device can be improved.

Abstract: A positive electrode active material for a lithium ion secondary battery contains a lithium metal composite oxide. The lithium metal composite oxide includes lithium (Li), nickel (Ni), cobalt (Co), and element M (M) in a mass ratio of Li:Ni:Co:M=1+a:1?x?y:x:y (wherein ?0.05?a?0.50, 0?x?0.35, 0?y?0.35, and the element M is at least one element selected from Mg, Ca, Al, Si, Fe, Cr, Mn, V, Mo, W, Nb, Ti, Zr, and Ta), wherein when a line analysis is performed with STEM-EELS from a surface of a particle of the lithium metal composite oxide to a center of the particle in a cross-section of the particle during charging at 4.3 V (vs. Li+/Li), a thickness of an oxygen release layer, in which an intensity ratio of a peak near 530 eV (1st) to a peak near 545 eV (2nd) at an O-K edge is 0.9 or less, is 200 nm or less.

Abstract: According to an embodiment of the present inventive concept, an electrolyte additive represented by the compounds of Chemical Formulas 1 to 4 may be provided. In addition, according to another embodiment of the present inventive concept, a method for preparing an electrolyte additive of the compounds of Chemical Formulas 1 to 4 may be provided, wherein the method for preparing the electrolyte additive includes reacting hexafluorophosphate and 2-monofluoromalonic acid, further adding an HF scavenger to the mixed solution produced by the reaction, and concentrating and drying the reaction solution obtained therefrom.

Abstract: The present invention relates to a lithium secondary battery having excellent battery performance at high voltage, wherein the lithium secondary battery according to the present invention includes a positive electrode which includes a positive electrode active material layer including a lithium nickel cobalt manganese-based oxide having an average particle diameter of primary particles of 3 ?m or more and a lithium cobalt-based oxide, a negative electrode which includes a negative electrode active material layer including a negative electrode active material, and an electrolyte, wherein a ratio of negative electrode capacity to positive electrode capacity is in a range of 1.06 to 1.15.

Abstract: A composite material for use as an electrode of an electrochemical cell comprises: a matrix that is provided by matrix particles that comprise an electrode active material; and a conductive fraction that is both electronically-conductive and ionically-conductive, the conductive fraction being provided by conductive particles that are distributed among the matrix particles. The conductive particles comprise either a material that is both ionically- and electronically-conductive; or a mixture of ionically-conductive particles and electronically-conductive particles, the electronically-conductive particles having a sphericity of at least 0.6. The conductive particles have a D90 value that is at least 10% of the D50 value of the matrix particles.

Abstract: A method for predicting a lifespan of a battery cell of the present invention includes: virtually dividing a capacity of a battery cell, which is a measurement object for lifespan prediction, into two or more capacity parts, and measuring charge and discharge cycle data for each of the capacity parts; correcting the charge and discharge cycle data by reflecting storage degeneration a positive electrode active material; and predicting a lifespan of the battery cell, based on the corrected charge and discharge cycle data.

Abstract: A mixture including: 99% to 99.9999% by weight of at least one lithium salt A; and 1 ppm to 10,000 ppm by weight of at least one potassium salt B. Also, a battery including at least one electrochemical cell, the electrochemical cell including a negative electrode, a positive electrode and the mixture.

Abstract: Substantially defect-free layered lithium nickel oxide materials of Formula (I): Li(1?x)(Ni(1?y)My)(1+x)O2 and Formula (II): LiaNibMc O2 are provided herein, wherein M is one or more metal selected from the group consisting of Co, Mn, Al, Mg, Ti, B, Zr, Nb, and Mo; 0?x?0.05; and 0?y?0.1, 0.97?a?1.03; 0.9?b?1; 0?c?0.1; and 0.97?(b+c)?1.03; and the material has a layered structure with no more than about 1.2 percent disorder between lithium and transition metal (TM) layers, as determined by structural refinement calculations on x-ray diffraction (XRD) data, compared to an ideal layered LiNiO2 structure. The materials can be formed by heating Ni(OH)2 or NiO with lithium hydroxide at a temperature in the range of about 650 to 680° C.

Abstract: A composite cathode active material represented by Lix(Co1?wM1w)yPO4 (Formula 1) having an olivine structure, wherein a unit-cell volume of the composite cathode active material is in a range of about 283 ?3 to about 284.6 ?3. A cathode including the composite cathode active material, and a secondary battery including the composite cathode active material are also disclosed. In Formula 1, M1 includes i) at least one of Sc, Ti, V, Cr, Cu, or Zn, and optionally at least one of Fe or Ni, and 0.9?x?1.1, 0.9?y?1.1, and 0<w?0.3.

Abstract: Systems and methods for use of perforated anodes in silicon-dominant anode cells may include a cathode, an electrolyte, and an anode, where the cathode and anode each comprise an active material on a current collector. Both of the current collector and active material may be perforated. For example, the current collector may be perforated and/or both the current collector and active material may be perforated. The battery may comprise a stack of anodes and cathodes. Each cathode of the stack may be perforated and/or each anode of the stack may be perforated. Each cathode of the stack may comprise two layers of active material on each side of the cathode where a first of the two layers of active material may be for prelithiation of anodes of the battery. A second of the two layers may be for lithium cycling of the battery.

Abstract: Provided are: a non-aqueous electrolyte solution that can improve the charged storage characteristics of a non-aqueous electrolyte battery under a high-temperature environment while containing FSO3Li; and a non-aqueous electrolyte battery having excellent charged storage characteristics under a high-temperature environment. The non-aqueous electrolyte solution contains FSO3Li and a specific amount of ions of a specific metal element.

Abstract: A positive-electrode active material for a magnesium secondary battery contains a composite oxide represented by the following composition formula: M1xM2yO2, where M1 is sodium, M2 is nickel and manganese, and 0<x+y?2.

Abstract: Anode active materials for lithium secondary batteries are provided. According to embodiments of the present disclosure, an anode active material includes: i) a first composite including at least two active silicon materials having different crystal sizes and a silicon oxide (SiOx) material (wherein 0<x?2); ii) a second composite including an active silicon material having a crystal size of about 24 nm or greater and a silicon oxide (SiOx) material (wherein 0<x?2), mixed with a carbonaceous material; or a mixture or combination of (i) and (ii). A lithium secondary battery is provided including an anode including any one of the anode active materials.

Abstract: A cathode active material includes a lithium manganese (Mn) iron (Fe) phosphate, wherein a mol ratio of Mn:Fe is from about 3:7 to about 9:1, the lithium manganese iron phosphate is an olivine structure, and the Mn and Fe in the olivine are present in an partially ordered or partially disordered sublattice.

Abstract: An electrode for lithium secondary battery and a method of manufacturing the same are disclosed. The electrode for lithium secondary battery comprised of an electric collector formed of a metal and a slurry coated on a portion of the electric collector includes a coated part including the portion of the electric collector, on which the slurry is coated, and the slurry, and an uncoated part including a remaining portion of the electric collector on which the slurry is not coated. The uncoated part includes a first uncoated part extended from the coated part and a second uncoated part extended from the first uncoated part and including a tab connection portion coupled to an electrode tab. A tensile strength of the first uncoated part is greater than a tensile strength of the tab connection portion.

Abstract: In a nonaqueous electrolyte secondary battery, a separator includes a substrate, a first filler layer disposed on one side of the substrate and containing phosphate salt particles, and a second filler layer disposed on the other side of the substrate and containing inorganic particles. The separator is disposed between a positive electrode and a negative electrode in such a manner that the side of the substrate which bears the first filler layer is directed to the positive electrode side.

Abstract: According to one embodiment, a method of producing a secondary battery is provided. The method includes preparing a battery architecture including a positive electrode, a negative electrode, and an electrolyte; adjusting a positive electrode potential to a range of 3.4 V to 3.9 V and a negative electrode potential to a range of 1.5 V to 2.0 V based on an oxidation-reduction potential of lithium, thereby providing a potential adjusted state; and holding the battery architecture in the potential adjusted state at a holding temperature of 50° C. to 90° C. The positive electrode includes a lithium-nickel-cobalt-manganese composite oxide. The negative electrode includes a niobium-titanium composite oxide. The electrolyte includes one or more first organic solvent having a viscosity of 1 cP or less.

Abstract: An electrochemical cell for an accumulator operating according to the principle of forming an alloy with the active material of the negative electrode during the charge process comprising: a negative electrode comprising, as active material, a material alloyable with an element M, M being a metal element; a positive electrode comprising, as active material, a conversion material; an electrolyte comprising at least one salt of M disposed between the negative electrode and the positive electrode.

Abstract: A method of diagnosing degradation of an electrode active material for a secondary battery including obtaining a first differential curve (dQ/dV) by differentiating an initial charge/discharge curve obtained by performing first charging and first discharging of the lithium secondary battery in a voltage range of 2.5 V to 4.2 V, and obtaining a second differential curve (dQ/dV) by differentiating a charge/discharge curve obtained by performing second charging and second discharging of the lithium secondary battery in a voltage range of 2.5 V to 4.2 V, and diagnosing whether a beta phase of the positive electrode active material has been formed by comparing maximum discharge peak values of the first differential curve and the second differential curve.

Abstract: Provided is a lithium secondary battery including a positive electrode layer composed of a lithium complex oxide sintered body, a negative electrode layer composed of a titanium-containing sintered body, a ceramic separator, an electrolytic solution, and an exterior body including a closed space, the closed space accommodating the positive electrode layer, the negative electrode layer, the ceramic separator, and the electrolytic solution, wherein the positive electrode layer, the ceramic separator, and the negative electrode layer are bonded together, the ceramic separator is composed of MgO and glass, the glass has an average grain size of 0.5 to 25 ?m, and a ratio of the average grain size of the glass to the average grain size of MgO is 1.5 to 85.

Abstract: Cathode materials, batteries, and methods of forming one or more electrodes for batteries are disclosed. A coated cathode material includes a lithium battery cathode material, a first sub-nanoscale lithium metal oxide coating on the lithium transition metal oxide and a sub-nanoscale metal oxide coating on top of the first sub-nanoscale lithium metal oxide coating. The first sub-nanoscale lithium metal oxide and the sub-nanoscale metal oxide coating are each less than 1 nm thick.

Abstract: An all-solid-state secondary battery includes: a cathode layer including a cathode active material, an anode layer including an anode current collector and an anode active material layer disposed on the anode current collector, the anode active material layer including an anode active material and amorphous carbon, and a solid electrolyte layer disposed between the cathode active material layer and the anode active material layer, wherein a weight ratio of the anode active material to the amorphous carbon is 1:3 to 1:1, and the anode layer has sheet resistance of about 0.5 milliohms-centimeters or less.

Abstract: The present application discloses a microfabricated micron-scale battery having excellent performance attributes. The battery using a titanium anode which is etched to form a plurality of raised features on the titanium anode. The raised features are coated conformally with a highly conductive metal. A layer of titanium is then formed over the highly conductive metal. This titanium layer is then oxidized to provide further small scale roughness. The roughness increases the surface area which improves the uptake of lithium ions by the anode. The battery can be combined with a titanium thermal ground plane to further enhance performance by removing heat from the battery.

Abstract: This electrode plate for a non-aqueous electrolyte secondary battery has a band-like core and a first active substance layer formed on at least a first surface of the core. A current-collecting lead is connected to an exposed section at which a portion of the first surface of the core is exposed in the longitudinal direction. The electrode plate for a non-aqueous electrolyte secondary battery has a second active substance layer which is more electroconductive than the first active substance layer and which is disposed on a portion of the first surface such that it adjoins with the exposed section.

Abstract: A power storage device with high capacity is provided. A power storage device with high energy density is provided. A highly reliable power storage device is provided. A long-life power storage device is provided. An electrode with high capacity is provided. An electrode with high energy density is provided. A highly reliable electrode is provided. Such a power storage device includes a first electrode and a second electrode. The first electrode includes a first current collector and a first active material layer. The first active material layer includes active material particles, spaces provided on the periphery of the active material particles, graphene, and a binder. The active material particles are silicon. The active material particles and the spaces are surrounded by the graphene and the binder.

Abstract: The present disclosure relates to a method of making core-shell and yolk-shell nanoparticles, and to electrodes comprising the same. The core-shell and yolk-shell nanoparticles and electrodes comprising them are suitable for use in electrochemical cells, such as fluoride shuttle batteries. The shell may protect the metal core from oxidation, including in an electrochemical cell. In some embodiments, an electrochemically active structure includes a dimensionally changeable active material forming a particle that expands or contracts upon reaction with or release of fluoride ions. One or more particles are at least partially surrounded with a fluoride-conducting encapsulant and optionally one or more voids are formed between the active material and the encapsulant using sacrificial layers or selective etching. The fluoride-conducting encapsulant may comprise one or more metals.

Abstract: The present technology is directed to a potassium metal battery, particularly a potassium metal secondary battery, that includes a cathode; an anode that includes potassium metal; and a non-aqueous electrolyte that includes a potassium salt as well as a solvent. The solvent may include dimethoxyethane, digylme, triglyme, tetraglyme, or a mixture of any two or more thereof.

Abstract: Provided are a lithium nickel manganese oxide composite material, a preparation method thereof and a lithium ion battery. The preparation method includes: a first calcining process is performed on a nano-oxide and a nickel-manganese precursor, to obtain an oxide-coated nickel-manganese precursor; and a second calcining process is performed on the precursor and a lithium source material, to obtain the lithium nickel manganese oxide, and a temperature of the first calcining process is lower than the second calcining process. A a lower temperature, the nano-oxide may be melted, a denser nano-oxide coating layer is formed on the surface of the precursor, so the oxide-coated nickel-manganese precursor is obtained. At a higher temperature, the nano-oxide, a nickel-manganese material and a lithium element may be more deeply combined. A problem that the nano-oxide layer is easy to fall off is solved, and cycle performance of the lithium nickel manganese oxide is greatly improved.

Abstract: A method for isolating a lithium precursor according to an embodiment of the present disclosure includes preparing a preliminary precursor mixture including a preliminary lithium precursor and a preliminary transition metal precursor, mixing the preliminary precursor mixture and a precipitation liquid in a reactor to form a precursor mixture, and injecting a non-reactive gas into the precursor mixture. Accordingly, the lithium precursor can be isolated with high yield and high efficiency.

Abstract: According to one embodiment, a battery is provided. The battery includes a positive electrode, and a negative electrode including a negative electrode active material-containing layer including a niobium-titanium composite oxide and a conductive agent that includes a carbon material. The negative electrode active material-containing layer includes a principal surface facing the positive electrode. Assuming that the thickness of the negative electrode active material-containing layer is A, a ratio (C2/C1) of carbon content ratio C2 at a depth of 0.5 A from the principal surface to carbon content ratio C1 at a depth of 1 ?m from the principal surface satisfies 2?C2/C1?30.

Abstract: The present disclosure relates to a method for manufacturing a negative electrode for an all solid state secondary battery, including the steps of: (S1) preparing a preliminary negative electrode including: a current collector; and a negative electrode active material layer formed on at least one surface of the current collector, and containing a plurality of negative electrode active material particles and a solid electrolyte; (S2) disposing a lithium layer on the negative electrode active material layer; (S3) dipping the preliminary negative electrode having the lithium layer disposed thereon in an organic solvent; and (S4) removing the lithium layer. The present disclosure also relates to a negative electrode for an all solid state secondary battery obtained by the method. The negative electrode for an all solid state secondary battery provides improved initial efficiency and cycle characteristics.

Abstract: An improved nanocomposite cathode material for lithium-ion batteries and method of making the same. The nanocomposite cathode material includes lithium iron silicate based nanoparticles with a conductive matrix of graphene sheets. The nanoparticles may be doped with at least one anion or cation.

Abstract: Compounds, particles, and cathode active materials that can be used in lithium ion batteries are described herein. Methods of making such compounds, powders, and cathode active materials are described. The particles have a particle size distribution with a D50 ranging from 10 ?m to 20 ?m.

Abstract: A button cell includes a housing having a cell cup with a flat bottom area and having a cell top with a flat top area. The button cell also includes an electrode-separator assembly winding disposed within the housing. The electrode-separator assembly winding includes a multi-layer assembly that is wound in a spiral shape about an axis. The multi-layer assembly includes a positive electrode formed from a first current collector coated with a first electrode material, a negative electrode formed from a second current collector coated with a second electrode material, and a separator disposed between the positive electrode and the negative electrode. The button cell further includes a winding core around which the multi-layer assembly is wound. The winding core provides a contact pressure on a first metal foil output conductor in an axial direction to facilitate electrical contact between the first metal foil output conductor and the housing.

Abstract: Provided are a negative electrode for a lithium secondary battery having reinforced insulating properties, which comprises a negative electrode active material layer; and a ceramic separating layer formed on the negative electrode active material layer, wherein the negative electrode active material layer has an arithmetic average surface roughness (Ra) of 0.01 ?m to 0.3 ?m, and the ceramic separating layer has a thickness of 1 ?m to 30 ?m, and a lithium secondary battery comprising the same.

Abstract: The disclosure relates to a process for preparing particulate materials having high electrochemical capacities that are suitable for use as anode active materials in rechargeable metal-ion batteries. In one aspect, the disclosure provides a process for preparing a particulate material comprising a plurality of composite particles. The process includes providing particulate porous carbon frameworks comprising micropores and/or mesopores, wherein the porous carbon frameworks have a D50 particle diameter of at least 20 ?m; depositing an electroactive material selected from silicon and alloys thereof into the micropores and/or mesopores of the porous carbon frameworks using a chemical vapour infiltration process in a fluidised bed reactor, to provide intermediate particles; and comminuting the intermediate particles to provide said composite particles.

Abstract: A lithium secondary battery including a positive electrode, a negative electrode comprising a negative electrode current collector, and an electrolyte interposed between the positive electrode and negative electrode. The lithium metal is formed on the negative electrode current collector by lithium ions migrating toward the negative electrode current collector after charge. The electrolyte comprises a sacrificial salt having an oxidation potential of 5 V or less with respect to lithium. The lithium secondary battery forms lithium metal while being blocked from the atmosphere, and thereby improves an existing problem caused by high reactivity of lithium metal. By including a sacrificial salt in an electrolyte, lithium consumption caused by an irreversible reaction of a negative electrode is reduced, which may prevent decline in the battery capacity and lifetime properties.

Abstract: A lithium ion secondary battery is provided. The lithium ion secondary battery includes an electrolytic tank having an accommodating space, a positive electrode disposed in the accommodating space, a negative electrode disposed in the accommodating space and spaced apart from the positive electrode, and an isolation film disposed between the positive electrode and the negative electrode. In the X-ray diffraction spectrum of a first surface of the electrolytic copper foil, a ratio of the diffraction peak intensity I(200) of the (200) crystal face of the first surface relative to the diffraction peak intensity I(111) of the (111) crystal face of the first surface is between 0.5 and 2.0. A ratio of the diffraction peak intensity I(200) of the (200) crystal face of a second surface relative to the diffraction peak intensity I(111) of the (111) crystal face of the second surface is between 0.5 and 2.0.

Abstract: Provided are a cathode active material composition, a cathode plate, a secondary battery, a battery module, a battery pack, and an electric device. In particular, the present application provides a cathode active material composition, including a cathode active material and a dispersant. The cathode active material composition of the present application can improve the poor dispersion of the cathode active material powder and the high viscosity of the slurry during the preparation of the cathode slurry, and further improve flexibility of the cathode plate.

Abstract: The invention pertains to certain fluoropolymer-based hybrid organic/inorganic composites, to polymer electrolytes obtained therefrom and to use of said polymer electrolytes in electrochemical devices.

Abstract: Provided is a negative electrode active material which is excellent in capacity, capacity retention ratio, and a coulombic efficiency when charging/discharging is repeated. The chemical composition of the alloy particles of the negative electrode active material of the present disclosure includes 0.50 to 3.00 mass % of oxygen, and alloy elements containing Sn: 13.0 to 40.0 at % and Si: 6.0 to 40.0 at %, with the balance being Cu and impurities. The structure of the alloy particles includes: one or more types selected from the group consisting of a phase having a D03 structure, and a ? phase; one or more types selected from the group consisting of an ? phase and an ?? phase; and a SiOx phase (x=0.50 to 1.70). The SiOx phase (x=0.50 to 1.70) has a volume fraction of 5.0 to 60.0% and the ?? phase has a volume fraction of 0 to 60.0%.

Abstract: The present invention provides a negative electrode for a lithium secondary battery, which includes a negative electrode current collector; and a negative electrode active material layer which is formed on the negative electrode current collector and includes a negative electrode active material including a silicon-based material, wherein the negative electrode active material includes lithium intercalated by pre-lithiation, and the extent of pre-lithiation of the negative electrode active material, calculated by a specific equation, is 5 to 50%.

Abstract: The present disclosure relates to a positive electrode active material for a lithium-sulfur battery, and the positive electrode active material of the present disclosure includes a sulfur-carbon composite, wherein the sulfur-carbon composite includes a porous carbon material and a sulfur-based material disposed on at least a portion of an inside of pores and a surface of the porous carbon material, wherein the sulfur-based material includes at least one of sulfur (S8) or a sulfur compound, and wherein the porous carbon material satisfies one or more of the following conditions: (1) a sum of particle size D10 and particle size D90 is 60 ?m or less; and (2) a broadness factor (BF) satisfying Equation 1 is 7 or less: Broadness factor (BF)=(particle size D90 of the porous carbon material)/(particle size D10 of the porous carbon material)??[Equation 1].

Abstract: Methods of making an anode for a lithium-based energy storage device such as a lithium-ion battery are disclosed. Methods may include providing a current collector. The current collector may include an electrically conductive layer and a surface layer overlaying over the electrically conductive layer. The surface layer may have an average thickness of at least 0.002 ?m. The surface layer may include a metal chalcogenide including at least one of sulfur or selenium. Methods may include depositing a continuous porous lithium storage layer onto the surface layer by a PECVD process. The continuous porous lithium storage layer may have an average thickness in a range of 4 ?m to 30 ?m and comprises at least 85 atomic % amorphous silicon.

Abstract: Provided is a binder composition for an all-solid-state secondary battery that can yield an all-solid-state secondary battery having excellent output characteristics and high-temperature cycle characteristics. The binder composition for an all-solid-state secondary battery contains a polymer, an anti-aging agent, and an organic solvent. The polymer includes a (meth)acrylic acid ester monomer unit in a proportion of not less than 25 mass % and not more than 95 mass % and has a gel content of 50 mass % or less. The anti-aging agent is contained in an amount of not less than 0.005 parts by mass and not more than 0.5 parts by mass per 100 parts by mass of the polymer.

Abstract: Disclosed is a separator for a lithium-sulfur battery and a lithium-sulfur battery including the same. In particular, disclosed is a separator for a lithium-sulfur battery including a porous substrate and an inorganic coating layer present on at least one surface of the porous substrate wherein the inorganic coating layer includes a modified montmorillonite substituted with at least one specific ion. The separator may include a uniform inorganic coating layer by including a modified montmorillonite, and thus adsorbs lithium polysulfide, thereby improving the capacity and lifetime characteristics of the lithium-sulfur battery.

Abstract: Provided is a composition for an electrochemical device functional layer capable of providing an electrochemical device having low volume expansion. The composition for an electrochemical device functional layer contains a solvent and a polymer including an oxide structure-containing monomer unit. The oxide structure-containing monomer unit has a structure indicated by the following formula (I) (in formula (I), R1 represents an optionally substituted alkylene group and n is a positive integer), and the polymer has a number-average molecular weight of not less than 5,000 and not more than 15,000.

Abstract: A lithium secondary battery comprising a positive electrode, a negative electrode, a lithium metal layer, and an electrolyte disposed between the positive electrode and the negative electrode. The negative electrode comprises a first protective layer formed on a negative electrode current collector, a second protective layer formed on the first protective layer opposite the negative electrode current collector, and a third protective layer formed inside and on one surface of the second protective layer opposite the first protective layer, and wherein the lithium metal layer is formed between the negative electrode current collector and the first protective layer in the negative electrode when lithium ions migrate from the positive electrode after charging.

Abstract: A negative electrode active material includes a first negative electrode active material particle, and the first negative electrode active material includes a silicon-based material. A Si2p spectrum obtained by measuring the first negative electrode active material particle in a state of 0.6 V (vs. Li/Li+) by X-ray photoelectron spectroscopy has a peak in a range from 99.0 eV to 105.0 eV, and a half width of the peak is 1.5 eV or more and 8.0 eV or less.