Germanium Nanowires via Molten-Salt Electrolysis for Lithium Battery Anode.

Liu, Huan; Wu, Tianhao; Zhang, Liqiang; Wang, Xin; Li, Haifeng; Liu, Shiqi; Zhang, Qi; Zhang, Xu et al. · ACS Nano · 2022

basic_science · Level V

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Abstract

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<sup>-1</sup> at 300 mA g<sup>-1</sup> and a capacity above 602.5 mAh g<sup>-1</sup> at 3000 mA g<sup>-1</sup> for 900 cycles. By <i>in situ</i> transmission electron microscopy and <i>in situ</i> 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 Li<sub>1.2</sub>Mn<sub>0.567</sub>Ni<sub>0.167</sub>Co<sub>0.067</sub>O<sub>2</sub> 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.