Phase-segregated SnSb alloy anode for lithium-ion battery

Alloy materials are promising in the anode of next-generation lithium-ion batteries (LIBs) due to their high theoretical capacities and suitable operating voltages. This study examines the effect of Sn[sbnd]Sb phase segregation on the electrochemical performance in LIBs. Distinct Sn, Sb, and SnSb intermetallic alloy phases were present in the partially alloyed SnSb sample (SnSb-PA), in contrast to the fully alloyed SnSb sample (SnSb-FA), which exhibited a single homogeneous SnSb phase. SnSb-PA exhibited superior electrochemical performance, achieving a gravimetric capacity of 821 mAh g⁻¹, a volumetric capacity of 2849 mAh cm⁻³, an initial Coulombic efficiency (ICE) of 94 %, and a capacity retention of 98.7 % over 100 cycles, which are significantly superior compared to those of SnSb-FA (127 mAh g⁻¹, 435 mAh cm⁻³, and capacity retention of 17.2 %). In SnSb-PA, crack formation was reduced and Li ion diffusivity was enhanced owing to a microstructure comprising nanoscale grains. SnSb-PA also displayed enhanced stress relaxation, which mitigated volume expansion and increased cycling stability. These findings underscore the critical role of grain structure in improving the mechanical and electrochemical stability of alloy-based anodes, providing a pathway for their application in next-generation LIBs.