Amorphous Germanium Nanomaterials as High‐Performance Anode for Lithium and Sodium‐Ion Batteries

Abstract Amorphous germanium (a‐Ge) is a promising anode material for lithium and sodium‐ion batteries (LIBs and SIBs) due to its higher capacity than traditional graphite materials. Herein, a method to prepare the a‐Ge nano‐materials with a particle size ≈10 nm is proposed by decomposing the CaGe Zintl phase at room temperature. For LIBs, a‐Ge has a high‐capacity retention of 80% even after 180 cycles (1375 mAh g −1 ). When employed as the anode for SIBs, two‐dimensional composites with the a‐Ge supported on the graphite nanosheets (a‐Ge@GNS) is configured, and a high reversible capacity of 526 mAh g −1 after 120 cycles is achieved. The preparation of such high‐performance amorphous Ge nanomaterials demonstrated in this work is low‐cost and environmentally‐friendly, and compared with other methods it is especially suitable for scaling‐up or mass production.