Enhancement of the Cyclability of a Si Anode through Co₃O₄ Coating by the Sol–Gel Method

A nano-Si/Co 3 O 4 core–shell nanostructured material has been successfully prepared using the sol–gel method. The reaction mechanism between Li and the nano-Si/Co 3 O 4 core–shell nanostructured electrode was investigated by ex situ analyses. Metallic Co, Li 21 Si 8, and amorphous Li 2 O phases were formed when fully lithiated, and an amorphous Si, Co 3 O 4, and Co phases were identified after charge, indicating that the Co 3 O 4 was partially reversible. The nano-Si/Co 3 O 4 core–shell nanostructured electrode showed excellent cyclability, with a reversible capacity of ca. 850 mAh/g over 100 cycles.