Metallic V5S8 microparticles with tunnel-like structure for high-rate and stable zinc-ion energy storage

Rechargeable aqueous zinc-ion batteries (AZIBs) are tremendously competitive in terms of cost-economy and safe-operation. However, their development is significantly hampered by the lack of stable cathode materials allowing robust zinc-ion diffusion. Herein, it is firstly reported that a facile synthesis V5S8 with tunnel-like crystal structure, even in micron-size form, can be investigated as a superior intercalated cathode material for AZIBs, which delievers a high capacity of 240 mAh g−1 at 0.1 A g−1 and a record capacity retention of 94% (182 mAh g−1) after 1000 cycles at a high current density of 10 A g−1. Density functional theory (DFT) calculations show that V5S8 has a strong metallic characteristic and an optimal zinc-ion diffusion path with a low hopping energy barrier, boosting the distinctly fast transport capability of both electrons and ions. Consequently, an unprecedented rate capacity retention of 80.75% was obtained when the current density underwent a hundred-fold change, and the ultrafast ion migration kinetics along with desirable pseudocapacitive behaviors were further confirmed. Moreover, using in-situ synchrotron X-ray diffraction, ex-situ X-ray photoelectron spectroscopy, and DFT calculations, this study provides significant insight into the reaction mechanism of the V5S8 cathode with self-adaptive multistage ion storage.