Abstract: A negative electrode includes a negative electrode active material layer, the negative electrode active material layer includes negative electrode active material particles, and the negative electrode active material particle includes a porous portion and a nonporous portion with heteroatoms. The heteroatom includes at least one of element boron, nitrogen, fluorine, phosphorus, or sulfur and is located on an interface, and the interface is a region, in the nonporous portion, formed from a bordering position between the nonporous portion and the porous portion to 0.5 ?m from the bordering position. The porous portion improves the lithium ion intercalation and deintercalation efficiency. In addition, boron, nitrogen, and other elements doped increase the gram capacity of the negative electrode active material, helping increase the energy density of the electrochemical apparatus.

Abstract: A composite material includes a graphite particle. A surface of the graphite particle is provided with a first region and a second region. The first region is made of graphite, and the second region includes a hard carbon layer. A surface area of the first region is denoted as A1 ?m2, and a surface area of the second region is denoted as A2 ?m2, 0?A1/A2?9. A thickness of the hard carbon layer is H nm, 5?H?500. By controlling the coating amount and coating area of the hard carbon to satisfy the above relationship, this application can improve energy density, capacity performance, and the like at the same time of enhancing dynamic performance.

Abstract: A negative active material includes composite particles. The composite particle includes a first region and a second region, where the first region includes a disordered carbon structure, and the second region includes an ordered carbon structure and/or a metal oxide structure. The negative active material of this application has a high gram capacity and active ion diffusion coefficient, so that a secondary battery containing such negative active material has a high energy density and excellent cycling performance, rate performance, and fast charging capacity.