Abstract: A negative electrode plate, including a negative current collector and a negative active material layer disposed on at least one side of the negative current collector. The negative active material layer includes a negative active material, including hard carbon particles and graphite particles. The hard carbon particles have a lamellar structure. Based on a quantity of the hard carbon particles, a quantity of the hard carbon particles with an aspect ratio of 3 to 7 accounts for a %, and 30?a?70. The face-to-face contact in the lamellar hard carbon active material in the negative electrode plate replaces the point-to-point contact in the hard carbon active material of conventional morphology, thereby effectively reducing the internal resistance of the negative active material layer, and effectively increasing the compacted density of the negative active material layer and reducing the porosity, and in turn, increasing the energy density of the lithium-ion battery.

Abstract: A negative active material in the negative active material layer includes hard carbon. An H/C value of the hard carbon is 0.05 to 0.18. A CB value of the electrochemical device is 0.95 to 1.05. This application uses hard carbon as a negative active material. By adjusting the H/C value of the hard carbon and the CB value of the electrochemical device, this application can increase the energy density without lithium precipitation, that is, alleviate lithium precipitation and increase the energy density concurrently.

Abstract: An electrochemical device includes a negative electrode plate and an electrolyte solution. The negative electrode plate includes a negative current collector and a negative active material layer, and the negative active material layer is located on the negative current collector. The negative active material layer includes a negative active material, the negative active material includes hard carbon and graphite, and a mass percent of the hard carbon in the negative active material is w. The electrolyte solution includes at least one of ethyl propionate or propyl propionate. A mass percent of the ethyl propionate and/or propyl propionate in the electrolyte solution is v, 5?v/w?21. The synergistic effect between the hard carbon and the electrolyte solvent enables the electrochemical device to meet requirements of both a high energy density and cost-effectiveness, and improves the low-temperature performance and C-rate performance of the electrochemical device.

Abstract: A negative electrode active material has a core-shell structure. The negative electrode active material includes a first shell and at least two core material particles located in the first shell. The core material includes hard carbon. The first shell includes a first shell material with a volumetric specific capacity of 800 mAh/cm3 or more.

Abstract: A hard carbon material has a pore structure. A scattering vector of the pore structure in a small-angle X-ray scattering spectrum is N1 nm?1, and 0.1?N1?7. The hard carbon material exhibits a scattering intensity convex peak. A full-width-at-half-maximum of the convex peak is L1 nm?1, and 0.1?L1?3.5. A pore volume of micropores of the hard carbon material measured by a nitrogen adsorption method is V2 cc/g, and 0<V2?0.01. The pore structure of the hard carbon material of this application includes micropores. During lithium storage, lithium ions can be stored in the micropores, thereby providing a reversible capacity. In addition, when used as a negative active material of an electrochemical device, the hard carbon material of this application endows the electrochemical device with a high energy density, a high first-cycle Coulombic efficiency, and good cycle performance.

Abstract: A negative active material, a negative electrode plate containing same, an electrochemical device, and an electrical device. The negative active material includes a hard carbon material. The hard carbon material includes a plurality of micropores and an average delithiation potential vs Li/Li+ of the hard carbon material is 0.15 V to 0.40 V.

Abstract: A negative electrode plate includes a negative current collector and a negative active material layer disposed on at least one side of the negative current collector. The negative active material layer includes a negative active material, the negative active material includes graphite and hard carbon, and a ratio of a mass percent ?H of hydrogen to a mass percent ?C of carbon in the hard carbon is 0.02??H/?C?0.20. The negative electrode plate enhances the high-temperature cycle performance of the electrochemical device.

Abstract: A hard carbon material includes a porous skeleton, a first element, and element zinc, where the first element includes at least one of element nitrogen, element sulfur, element boron, element phosphorus or element selenium. A percentage of the first element with respect to a total mass of the hard carbon material is A1%, and a percentage of element zinc with respect to the total mass of the hard carbon material is A2%, where the hard carbon material satisfies 1.5?A1/A2?5. When applied to an electrochemical apparatus, the hard carbon material can significantly improve the energy density of the electrochemical apparatus.

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.