Pillaring Effect of K Ion Anchoring for Stable V2O5-based Zinc-Ion Battery Cathodes

Aqueous zinc-ion batteries (ZIBs) have attracted widespread attention due to their advantages in safety and environmental benignity. However, achieving a cathode material with stable electrochemical performance for such a system remains an ongoing challenge. Herein, a K0.5V2O5 cathode has been designed and synthesized by intercalating of K+ into V2O5, thus constructing a stable crystal structure by forming chemical bonds between V2O5 layers. The successful intercalation of K+ has been confirmed by a series of experimental tests and Vienna Ab-initio Simulation Package simulation. These layer-interlinking chemical bonds act as "pillars" to strongly hold the V2O5 layers together and protect them from dissolution. Furthermore, the K0.5V2O5 electrode also exhibits excellent durability (about 150 mA h g(-1) at 5 A g(-1) after 3000 cycles). More impressively, even after standing for three days in the solution of 3 M ZnSO4 electrolyte, the K0.5V2O5 electrode still maintains a high capacity of 92.2 mA h g(-1) after 150 cycles, demonstrating its outstanding stability and tolerance in such aqueous electrolyte.