Directly Deposited Antimony on a Copper Silicide Nanowire Array as a High‐Performance Potassium‐Ion Battery Anode with a Long Cycle Life

Abstract

AbstractAntimony (Sb) is a promising anode material for potassium‐ion batteries (PIBs) due to its high capacity and moderate working potential. Achieving stable electrochemical performance for Sb is hindered by the enormous volume variation that occurs during cycling, causing a significant loss of the active material and disconnection from conventional current collectors (CCs). Herein, the direct growth of a highly dense copper silicide (Cu15Si4) nanowire (NW) array from a Cu mesh substrate to form a 3D CC is reported that facilitates the direct deposition of Sb in a core‐shell arrangement (Sb@Cu15Si4 NWs). The 3D Cu15Si4 NW array provides a strong anchoring effect for Sb, while the spaces between the NWs act as a buffer zone for Sb expansion/contraction during K–cycling. The binder‐free Sb@Cu15Si4 anode displays a stable capacity of 250.2 mAh g−1 at 200 mA g−1 for over 1250 cycles with a capacity drop of ≈0.028% per cycle. Ex situ electron microscopy revealed that the stable performance is due to the complete restructuring of the Sb shell into a porous interconnected network of mechanically robust ligaments. Notably, the 3D Cu15Si4 NW CC is expected to be widely applicable for the development of alloying‐type anodes for next‐generation energy storage devices.