Cubic crystal-structured Ge2Sb2Te5 with cation vacancies for enhanced lithium/sodium ion storage

Abstract

The development of kinetics-favorable and interfacial-stabilizing electrode materials is critical for temperature-tolerant energy conversion and storage devices, yet remains insufficiently explored. In this study, we present cation vacancy-rich Ge₂Sb₂Te₅ semimetal as an anode material for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Ge₂Sb₂Te₅ demonstrates exceptional electrochemical performance compared to other metal tellurides and exhibits impressive kinetics and interface stability at low temperatures. Experimental results indicate that the synergistic interactions between germanium/antimony vacancies and tellurium atoms, along with accelerated kinetics, enhanced electrical conductivity, and stabilized interfacial properties of Ge₂Sb₂Te₅, significantly contribute to its improved electrochemical activity. This material enables the LIBs and SIBs that operate effectively at low temperatures, achieving high discharge capacities of 287 and 161 mAh g⁻¹ for half-cells at −40°C, and an impressive energy density of 278 and 149 Wh kg⁻¹ for full cells at −20°C, respectively. This study provides valuable insights into kinetic activity and interfacial-stabilized electrochemical reactions, thereby facilitating the application of LIBs and SIBs in harsh environments.