Germanium-Based Electrode Materials for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) with superior energy density, rate capability, and cyclability are critically needed for next-generation portable electronics and electric vehicles. Germanium (Ge) is a promising candidate material for the high-capacity anode of LIBs. Although the cost of Ge is the main barrier for its wide application in large-scale electrochemical energy storage, the electrochemical performance of Ge in LIBs is interesting from both scientific and engineering perspectives. Compared to silicon (Si), Ge has received much less attention, despite the relatively high electronic conductivity and high lithiation-delithiation rate in Ge. In this Concept, we review recent progress in the in situ electrochemical study of the lithiation and delithiation mechanisms in Ge nanowires and nanoparticles. Insights into the nanostructural evolution and mechanical degradation during electrochemical reactions are highlighted. Critical unresolved questions are raised and prospects for the future research of Ge-based electrodes are discussed.