A negative electrode material includes a silicon-based material, where a particle of the silicon-based material includes at least one recessed portion, and the recessed portion is 50 nm to 20 μm in width, and 50 nm to 10 μm in depth. The recessed structure leaves room for the silicon-based material to swell, thereby solving the problem of large volume swelling of the silicon-based material. In addition, when the silicon-based material with the recessed structure is composited with a carbon material, a conductive agent, and the like to form a negative electrode plate, small particles of the carbon material and the conductive agent are embedded into the recessed portion of the silicon-based material, solving the problem of low compacted density of the silicon-based negative electrode material with a recessed structure, and compensating for the low volumetric energy density of the recessed structure.

A negative electrode active material includes a carbon material, where the carbon material has a specific degree of graphitization and aspect ratio distribution. A degree of graphitization Gr of the carbon material measured by an X-ray diffraction analysis method is 0.82 to 0.92, and based on a total quantity of particles of the carbon material, a proportion of particles with an aspect ratio greater than 3.3 in the carbon material is less than 10%. The negative electrode active material helps to improve cycle performance of the electrochemical apparatus. FIG. 1.

An electrode binder for a lithium secondary battery, and an electrode and a lithium secondary battery, including the electrode binder. The electrode binder includes: a cellulose-based graft copolymer grafted with a compound having an ion-hopping site; and a polyacrylate-based polymer having an anionic group via an exchange with a cation. By including the electrode binder in at least one of the positive electrode and the negative electrode, it is possible to provide a lithium secondary battery capable of enhancing fast charging/discharging behavior efficiency of the electrode by reducing electrode resistance generated inside the electrode during charging/discharging.

A natural graphite-based modified composite material, a preparation method therefor, and a lithium ion battery comprising the modified composite material. The natural graphite-based modified composite material comprises natural graphite and non-graphitized carbon coated on the inner and outer surfaces of the natural graphite. The preparation method comprises: (1) subjecting spherical natural graphite to isotropic treatment; (2) performing granularity control and shaping treatment; (3) subjecting the inner surface and the outer surface of the material obtained in step (2) to simultaneous modification; and (4) performing carbonization, so as to obtain a natural graphite-based modified composite material.

An electrode for batteries that does not include a metal-film-type current collector is disclosed herein. In some embodiments, the electrode comprises a composite having a core-shell structure including a core having an electrode active material, and a metal material coated on or doped in the surface of the core. A secondary battery having the electrode has increased capacity and energy density and exhibits improved lifespan characteristics.

An electrode for batteries that does not include a metal-film-type current collector is disclosed herein. In some embodiments, the electrode comprises a composite having a core-shell structure including a core having an electrode active material, and a metal material coated on or doped in the surface of the core. A secondary battery having the electrode has increased capacity and energy density and exhibits improved lifespan characteristics.

A lithium-ion battery includes: 1) an anode; 2) a cathode; and 3) an electrolyte disposed between the anode and the cathode and including lithium ions. The anode includes a graphene framework film including interconnected graphene sheets, and the graphene framework film has a specific surface area of 600 m.sup.2 g.sup.−1 or more.

A lithium-ion battery includes: 1) an anode; 2) a cathode; and 3) an electrolyte disposed between the anode and the cathode and including lithium ions. The anode includes a graphene framework film including interconnected graphene sheets, and the graphene framework film has a specific surface area of 600 m.sup.2 g.sup.−1 or more.

A negative active material for a rechargeable lithium battery includes a carbon-based active material including highly crystalline natural graphite and artificial graphite. The carbon-based active material has a peak intensity ratio (P2/P4) of about 0.3 to about 0.4, wherein P2 refers to the 101 peak of a rhombohedral crystal grain and P4 refers to the 101 peak of a hexagonal crystal grain, as measured by X-ray diffraction.

A negative active material for a rechargeable lithium battery includes a carbon-based active material including highly crystalline natural graphite and artificial graphite. The carbon-based active material has a peak intensity ratio (P2/P4) of about 0.3 to about 0.4, wherein P2 refers to the 101 peak of a rhombohedral crystal grain and P4 refers to the 101 peak of a hexagonal crystal grain, as measured by X-ray diffraction.