Negative electrode material, negative electrode containing negative electrode material, and negative electrode manufacturing method

A negative electrode, comprising:

• a negative electrode material, the negative electrode material comprises a silicon-containing material and a fluorocarbon coated on a surface of the silicon-containing material, the fluorocarbon is at least one of fluorinated graphite, fluorinated hard carbon, fluorinated soft carbon, fluorinated carbon nanotube, or fluorinated graphene;
• wherein based on a total weight of the negative electrode material, a weight percent content of the fluorocarbon is greater than 15% and less than or equal to 20%;
• wherein the negative electrode material has a ratio B/A ranging from 2.5 to 3.0,
• wherein the ratio B/A is a ratio of a maximum value B of differentials dQ/dV within a working electrode potential range of 0.4V-0.55V to a maximum value A of differentials dQ/dV within a working electrode potential range of 0.2V-0.35V, as determined by measuring a battery comprising a negative electrode made of the negative electrode material as a working electrode, metallic lithium as a counter electrode, and an electrolyte containing a lithium-ion conductive substance, during delithiation of the negative electrode material, based on a curve of differential dQ/dV plotted against working electrode potential V, wherein the differential dQ/dV is obtained by differentiating a charge/discharge capacity Q with respect to the working electrode potential V.

A method of manufacturing a negative electrode, comprising:

• forming a negative electrode containing a negative electrode material;
• and
• performing steps of lithiating and delithiating the negative electrode, wherein
• the negative electrode material comprises a silicon-containing material and a fluorocarbon coated on a surface of the silicon-containing material, and the silicon-containing material comprises at least one of pure silicon, silicon carbon, a silicon alloy, or a silicon oxide;
• wherein the fluorocarbon is at least one of fluorinated graphite, fluorinated hard carbon, fluorinated soft carbon, fluorinated carbon nanotube, or fluorinated graphene;
• wherein based on a total weight of the negative electrode material, a weight percent content of the fluorocarbon is greater than 15% and less than or equal to 20%;
• and
• in the steps of lithiating and delithiating, a ratio B/A of a maximum value B in differentials dQ/dV with respect to 0.4V-0.55V to a maximum value A in differentials dQ/dV with respect to 0.2V-0.35V is 2.5-3.0 when the negative electrode material is electrified in a delithiation direction in a case of charging and discharging a battery that comprises the negative electrode used as a working electrode, metallic lithium used as a counter electrode, and an electrolyte containing a lithium-ion conductive substance, and in a case of plotting a curve of a relationship between a differential dQ/dV and a working electrode potential V, wherein the differential dQ/dV is obtained by differentiating a charge/discharge capacity Q with respect to the working electrode potential V.