SILICON-BASED ALLOY NEGATIVE ELECTRODE MATERIAL FOR POWER STORAGE DEVICE, AND ELECTRODE ARRANGED BY USE THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a Si-based alloy negative electrode material superior in charge and discharge characteristics.SOLUTION: A Si-based alloy negative electrode material for a power storage device such that its charging and discharging are accompanied by lithium ion movement comprises: a Si primary phase including Si; and a compound phase including Si and at least one element other than Si. The compound phase has a phase including at least two phases of a phase including Si and Ni, a phase including Si and Ti, and a phase including Si, Ni and Ti. Alternatively, the compound phase has a phase including Si, Ni and Ti. The Si primary phase has a Si crystallite size of 30 nm or less. The compound phase including a combination of Si and Ni or a combination of Si and Ti has a crystallite size of 40 nm or less. An electrode comprises: the Si-based alloy negative electrode material.SELECTED DRAWING: Figure 1