Designing air-stable vanadium tetrasulfides anode materials via C[sbnd]O[sbnd]S bonding for potassium-ion and sodium-ion batteries

Abstract

Sodium-ion (SIBs) and potassium-ion batteries (PIBs) have attracted intensive attention as promising alternatives to lithium-ion batteries (LIBs) due to abundant natural resources and similar electrochemical characteristics. However, the progress of developing appropriate host materials for both Na+ and K+ ions storage still remains great challenges. Herein, we rationally designed and synthesized nano-spiral structured VS4 wrapped with reduced graphene oxide via COS bonding and served as the anode materials for SIBs and PIBs. Thanks to the air-stability, enhanced electronic conductivity, and enrich active sites, VS4@RGO composite presents an excellent discharge capacity of 475 mA h g−1 in SIBs and 225 mA h g−1 in PIBs at a current density of 5 A g−1, as well as capacity retention of almost 100% after 500 cycles. Particularly, the desirable rate capability could relevant to the rapid kinetic and interfacial storage suggested by quantitative study. Moreover, the intercalation and conversion reaction mechanism during K+ ions storage processes is fundamentally exposed via ex-situ X-ray diffraction, which could collaborative deliver high specific capacity and superior electrochemical reversibility.