PVP surface modification layer spacing and vacancy enhanced zinc ions storage and stability

Zinc ion batteries (ZIBs) have attracted extensive research in the field of electrochemical energy storage due to their lower cost, and higher safety. However, due to the large hydration radius of zinc ions have a large hydrated ionic radius, which makes it difficult to embed zinc ions in the cathode material and affects the electrochemical Therefore, the study of suitable cathode materials is one of the keys to the practical application of aqueous zinc ion batteries. In this paper, a functional cathode combining PVP as a surfactant and VS4 was designed with increased chain spacing and V3+ self-doping. This effectively induces abundant sulfur vacancies and selectively exposes a large amount of surface active surface (020), leading to improved Zn2+ intercalation kinetics, fast electrolyte penetration, and high process structural stability during insertion/extraction. Therefore, this new PVP-VS4 structure exhibits excellent electrochemical performance as the cathode of Zn-ion batteries, with a discharge specific capacity of 343 mAh g−1 at 0.1 A g−1; and a discharge specific capacity of 222 mAh g−1 after 2000 cycles at a current density of 2 A g−1, with a capacity retention rate close to 100 %. The fast reaction kinetics of the interaction reaction was further confirmed by corona intermittent titration (Gitt). Using a number of systematic studies and investigations of the pseudocapacitor contribution, we also concluded the energy storage mechanism and the ideal pseudocapacitor behavior. Moreover, PVP-VS4 is more resistant to self-discharge than the support VS4. In addition, we designed PVP-MnOx composites and PVP-induced co-engineering provides new and original opportunities to develop a range of efficient intercalation materials for the next energy storage technology.