Germanium Nanowires via Molten-Salt Electrolysis for Lithium Battery Anode

Germanium (Ge)-based materials can serve as promising anode candidates for high-energy lithium-ion batteries (LIBs). However, the rapid capacity decay caused by huge volume expansion severely retards their application. Herein, we report a facile and controllable synthesis of Ge nanowire anode materials through molten-salt electrolysis. The optimal Ge nanowires can deliver a capacity of 1058.9 mAh g-1 at 300 mA g-1 and a capacity above 602.5 mAh g-1 at 3000 mA g-1 for 900 cycles. By in situ transmission electron microscopy and in situ X-ray diffraction, the multiple-step phase transformation and good structural reversibility of the Ge nanowires during charge/discharge are elucidated. When coupled with a lithium-rich Li1.2Mn0.567Ni0.167Co0.067O2 cathode in a full battery, the Ge nanowire anode leads to a relatively stable capacity with a retention of 84.5% over 100 cycles. This research highlights the significance of molten-salt electrolysis for the synthesis of alloy-type anode materials toward high-energy LIBs.