A negative electrode active material particle with little deterioration is provided. Alternatively, a novel negative electrode active material particle is provided. Alternatively, a power storage device with little deterioration is provided. Alternatively, a highly safe power storage device is provided. Alternatively, a novel power storage device is provided. The electrode includes an active material and a conductive additive; the active material contains a metal or a compound including one or more elements selected from silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, and indium; the conductive additive contains a graphene compound; and the graphene compound contains fluorine.

Provided is a positive electrode for a non-aqueous electrolyte secondary battery, the positive electrode comprising: a positive electrode current collector; and a positive electrode mixture layer formed on the surface of the positive electrode current collector. The positive electrode mixture layer contains at least carbon fibers and a positive electrode active material containing a lithium-transition metal composite oxide, wherein the lithium-transition metal composite oxide has a layered rock salt structure, is substantially free of Co, and contains at least Ni, Al, and Sr.

An object of the present invention is to provide composite particles capable of suppressing oxidation over time of a Si—C composite material. Composite particles (B) of the present invention contains composite particles (A) containing carbon and silicon; and amorphous layers coating surfaces thereof, where the composite particles (B) have I.sub.Si/I.sub.G of 0.10 or more and 0.65 or less, and have R value (I.sub.D/I.sub.G) of 1.00 or more and 1.30 or less, when a peak due to silicon is present at 450 to 495 cm.sup.−1, an intensity of the peak is defined as I.sub.Si, an intensity of a G band (peak intensity in the vicinity of 1600 cm.sup.−1) is defined as I.sub.G, and an intensity of a D band (peak intensity in the vicinity of 1360 cm.sup.−1) is defined as I.sub.D in a Raman spectrum, and where the composite particles (B) have a full width at half maximum of a peak of a 111 plane of Si of 3.0 deg. or more using a Cu-Kα ray in an XRD pattern.

An anode piece for a lithium battery having both high safety and high capacity, and a preparation method and a use therefor, the anode piece being mixed with a lithium-rich compound, the lithium-rich compound being at least one selected from lithium-rich manganese-based solid solution, a lithium-rich solid electrolyte or a lithium-separated silicon oxide. Li ions can be pulled away from the lithium-rich compound in extreme conditions such as overcharging, internal short circuiting, external short circuiting, thermal abuse, piercing, compressing or overheating, thereby filling in lithium vacancies in the anode material, stabilizing the crystal lattice structure of the anode material, improving safety performance in a battery manufactured by using the material, and allowing the anode piece to maintain excellent cycle performance at higher area capacities.

A positive electrode material, including a composite material, where the composite material includes a metal fluoride, a molar ratio of fluorine F to metal element M in the metal fluoride is y, and a molar ratio of fluorine F to metal element M in the composite material is z, where y<z≤y+2; and M includes at least one of Al, Cu, Co, Ni, Mn, Fe, or Ag. The positive electrode material in this application has advantages such as wide raw material sources, simple preparation processes, easy to operate, and low production costs. Lithium batteries prepared by using the positive electrode material in this application have increased specific capacity and improved rate performance and cycling performance of the positive electrode material, and good charge and discharge performance.

The positive electrode active material with lithium composite oxide A containing W and Ni and W-free lithium composite oxide B containing Ni. Regarding the lithium composite oxide A, the proportion of Ni relative to the total moles of metal elements except for lithium is 30 to 60 mol %, 50% particle size D50 is 2 to 6 μm, 10% particle size D10 is 1.0 μm or more, and 90% particle size D90 is 6.8 μm or less. Regarding the lithium composite oxide B, the proportion of Ni relative to the total moles of metal elements except for lithium is 50 to 95 mol %, 50% particle size D50 is 10 to 22 μm, 10% particle size D10 is 7.0 μm or more, and 90% particle size D90 is 22.5 μm or less. The mass ratio of the lithium composite oxide B to the lithium composite oxide A is 1:1 to 5.7:1.

An anode for a lithium secondary battery includes an anode current collector, a first anode active material layer formed on at least one surface of the anode current collector and including a silicon-based active material and a graphite-based active material, and a second anode active material layer formed on the first anode active material layer and including a porous structure as an active material. The porous structure includes carbon-based particles including pores, and a silicon-containing coating formed at an inside of the pores of the carbon-based particles or on the surface of the carbon-based particles.

A negative electrode plate, a secondary battery, a battery module, a battery pack, and an electrical device are provided. The negative electrode plate includes a negative current collector and a negative film layer disposed on the negative current collector. The negative film layer includes a first negative film layer and a second negative film layer. The second negative film layer is located between the negative current collector and the first negative film layer. The second negative film layer includes a metal element M, and an atomic radius r.sub.M of M and an atomic radius r.sub.Li of Li satisfy

[00001]$0<.Math.\frac{r_M-r_{\mathrm{Li}}}{r_{\mathrm{Li}}}.Math.\times 100\%\le 12\%.$

This application can effectively suppress precipitation of lithium metal on the surface of the negative electrode plate, and significantly improve kinetic performance, cycle performance, and safety performance of the secondary battery.

A secondary battery, and a battery module, a battery pack, and an electric apparatus containing the same are provided. The secondary battery includes: an electrolyte having a specific percentage of a low-viscosity solvent, a specific percentage of a high-dielectric-constant solvent, and a negative electrode having a negative electrode active material layer, and the secondary battery satisfies the relational expression:

[00001]$1\times {10}^{-4}4\le \frac{B\times C\times P}{ \mathrm{OI}\times \mathrm{CW}}\le 1\times {10}^{-3}$

where B is the percentage of the low-viscosity solvent in total solvent in the electrolyte by mass; C is a percentage of an electrolyte salt in the electrolyte by mass; P is a porosity of the negative electrode active material layer; CW is a coating weight of the negative electrode active material layer, measured in mg/cm.sup.2; and OI is an orientation index of the negative electrode active material layer.

This application provides a lithium-nickel-manganese-based composite oxide material, where a K value of the lithium-nickel-manganese-based composite oxide material ranges from 1 to 2, and the K value is calculated based on the following formula: K=D.sub.v50/d.sub.v50, where d.sub.v50 is a volume median crystallite diameter of crystal particles of the lithium-nickel-manganese-based composite oxide material; and D.sub.v50 is a volume median particle diameter of the lithium-nickel-manganese-based composite oxide material.