High Conductivity Cu3Ge and High-Capacity GeO2 Synergistically Enhance a Continuous Channel Ge-Based Anode for Lithium-Ion Batteries with Long-Life and Scalable Preparation

The high theoretical capacity of germanium (Ge) is considerably restricted in practical applications due to the low conductivity and large volume variation range. The complex preparation process will further hinder the development of Ge anodes in lithium-ion batteries. In this paper, the Ge/Cu3Ge/ GeO2 composites with a continuous channel structure are composed of conductive Cu3Ge and high-capacity GeO2 dispersed in a Ge matrix, which were prepared by melt spinning, de-alloying, and oxidation in easy massive production. The optimized sample of D-Cu2Ge8-600 showed excellent cycling performance with a specific capacity of 875.7 mAh g-1 after 500 cycles at a current density of 0.1 A g-1. D-Cu2Ge8-600 also presents outstanding electrochemical performance in a full cell composed of commercial LiCoO2. The high lithium storage performance is inextricably attributed to that Cu3Ge and GeO2 allow Ge nanoparticles to be uniformly dispersed in a continuous channel structure providing volume space. Among them, the Cu3Ge phase acts as a conductive network. Concurrently, GeO2 improves the specific capacity of the whole electrode material. The easily prepared composites on a large scale could provide a novel route for future practical applications of Si-and Ge-based anode materials.