Lithium-ion battery and method of manufacturing the same

Abstract

The lithium-ion battery includes a positive electrode, a negative electrode, and an electrolyte. The negative electrode contains a negative electrode active material. The negative electrode active material contains a silicon material. The silicon material contains a silicon alloy phase and a silicate phase. The silicon alloy phase has a three-dimensional network structure. The silicate phase is arranged in a mesh of the three-dimensional network structure. The three-dimensional network structure has an average mesh size of 2.8 nm to 3.5 nm.

What is claimed is: 
     
         1 . A lithium-ion battery comprising:
 a positive electrode;   a negative electrode; and   an electrolyte, wherein:   the negative electrode contains a negative electrode active material;   the negative electrode active material contains a silicon material;   the silicon material contains a silicon alloy phase and a silicate phase;   the silicon alloy phase has a three-dimensional network structure;   the silicate phase is arranged in a mesh of the three-dimensional network structure; and   the three-dimensional network structure has an average mesh size of 2.8 nm to 3.5 nm.   
     
     
         2 . The lithium-ion battery according to  claim 1 , wherein the negative electrode active material further contains a carbon material. 
     
     
         3 . A manufacturing method of a lithium-ion battery comprising:
 assembling the lithium-ion battery; and   performing an initial charging on the lithium-ion battery, wherein:   the lithium-ion battery includes a positive electrode, a negative electrode, and an electrolyte;   the negative electrode contains a negative electrode active material;   the negative electrode active material contains a precursor of a silicon material;   the precursor has a composition represented by SiO x  where a relationship of 0<x<2 is satisfied;   the initial charging includes a first step and a second step;   in the first step, the charging is performed to an intermediate voltage at a first current rate;   in the second step, the charging is performed from the intermediate voltage to a maximum voltage at a second current rate;   the first current rate is lower than 0.5 C;   the second current rate is higher than the first current rate; and   the intermediate voltage is 3.75 V or higher.   
     
     
         4 . The manufacturing method of the lithium-ion battery according to  claim 3 , wherein the negative electrode active material further contains a carbon material.