Negative electrode for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery
View Patent ↗A negative electrode constituting a non-aqueous electrolyte secondary battery, which is an example of an embodiment, comprises a negative-electrode mixture layer including a negative-electrode active material and a binder agent. The negative electrode includes, as the binder agent, at least a polymer constituted by a constituent unit A represented by formula (1), a constituent unit B represented by formula (2), and a constituent unit C represented by formula (3). The molar ratio (l/m) of the constituent unit A to the constituent unit B is from 0.2 to 1.8.
1. A negative electrode for non-aqueous electrolyte secondary battery, the negative electrode comprising a negative electrode mixture layer including a negative electrode active material and a binder, wherein
the negative electrode includes, as the negative electrode active material, a silicon oxide represented by SiO x (where 0.5≤x≤1.5), the silicon oxide having a structure in which Si is distributed in an amorphous SiO 2 ,
the negative electrode includes, as the binder, at least a polymer comprising a constituent unit A represented by formula (1), a constituent unit B represented by formula (2), and a constituent unit C represented by formula (3), and
a molar ratio (Um) of the constituent unit A to the constituent unit B is from 0.2 to 1.8, and
a molar ratio (n/(1+m+n)) of the constituent unit C to a total molar amount of the constituent units A, B, and C of the polymer is from 0.078 to 0.16, wherein:
in formula 1, R1 denotes a straight chain alkyl group containing 1 to 4 carbons,
in formula 2, R2 denotes an alkyl group containing 1 to 4 carbons, and
in formula 3, M denotes H and/or a monovalent metal atom.
2. The negative electrode for non-aqueous electrolyte secondary battery according to claim 1 , wherein an amount of a surfactant having a molecular weight of less than 5000 contained in the negative electrode mixture layer is less than 10 ppm.
3. The negative electrode for non-aqueous electrolyte secondary battery according to claim 1 , wherein the M in the constituent unit C of the polymer is Li.
4. The negative electrode for non-aqueous electrolyte secondary battery according to claim 1 , wherein a glass transition temperature (Tg) of the polymer is from −40 to 30° C.
5. The negative electrode for non-aqueous electrolyte secondary battery according to claim 1 , wherein the polymer has a swelling scale factor of from 1.9 to 40, the swelling scale factor being obtained by immersing the polymer in a solvent prepared by mixing ethylene carbonate and diethyl carbonate at a volume ratio of 1:1.
6. The negative electrode for non-aqueous electrolyte secondary battery according to claim 1 , wherein a porosity of the negative electrode mixture layer is from 40 to 60%.
7. The negative electrode for non-aqueous electrolyte secondary battery according to claim 1 , wherein a contained amount of the polymer in the negative electrode mixture layer is from 0.3 to 2 parts by weight relative to 100 parts by weight of the negative electrode active material.
8. A non-aqueous electrolyte secondary battery comprising the negative electrode for non-aqueous electrolyte secondary battery according to claim 1 .