NEGATIVE ELECTRODE MATERIAL FOR LITHIUM-ION SECONDARY BATTERY, METHOD OF EVALUATING SAME, AND METHOD OF PRODUCING SAME, NEGATIVE ELECTRODE FOR LITHIUM-ION SECONDARY BATTERY, AND LITHIUM-ION SECONDARY BATTERY
A negative electrode material for a lithium-ion secondary battery includes graphite particles satisfying the following Formula (1): [Springback rate×7.6]+[Compressive load (kN/cm 2 )]≥4.2 (1).
1 . A negative electrode material for a lithium-ion secondary battery comprising graphite particles satisfying the following Formula (1):
[Springback rate×7.6]+[Compressive load (kN/cm 2 )]≥4.2 (1).
2 . The negative electrode material for a lithium-ion secondary battery according to claim 1 , wherein the compressive load of the graphite particles is 2.0 kN/cm 2 or more.
3 . The negative electrode material for a lithium-ion secondary battery according to claim 1 , wherein the springback rate of the graphite particles is 0.25 or more.
4 . The negative electrode material for a lithium-ion secondary battery according to claim 1 , wherein the graphite particles comprises composite particles having a structure in which a plurality of flat graphite particles are stacked.
5 . A method of evaluating a negative electrode material for a lithium-ion secondary battery comprising, evaluating a negative electrode material for a lithium-ion secondary battery using a regression formula obtained by multiple regression analysis with a springback rate of graphite particles included in the negative electrode material for a lithium-ion secondary battery and a compressive load (kN/cm 2 ) of the graphite particles as explanatory variables and a liquid absorption time of a negative electrode including the negative electrode material for a lithium-ion secondary battery as an objective variable.
6 . A method of producing a negative electrode material for a lithium-ion secondary battery comprising producing a negative electrode material for a lithium-ion secondary battery based on an evaluation result of a negative electrode material for a lithium-ion secondary battery using the evaluation method of a negative electrode material for a lithium-ion secondary battery according to claim 5 .
7 . A method of producing a negative electrode material for a lithium-ion secondary battery comprising producing the negative electrode material for a lithium-ion secondary battery according to claim 1 , wherein the method comprises a step of graphitizing coke.
8 . The method of producing a negative electrode material for a lithium-ion secondary battery according to claim 7 , wherein the coke has a thermal expansion coefficient after firing at 1400° C. of 2.30×10 −6 /° C. or more.
9 . A negative electrode for a lithium-ion secondary battery, comprising:
a negative electrode material layer comprising the negative electrode material for a lithium-ion secondary battery according to claim 1 , and a current collector.
10 . A lithium-ion secondary battery, comprising: the negative electrode for a lithium-ion secondary battery according to claim 7 ; a positive electrode; and an electrolytic solution.