Suppressing vanadium dissolution of V2O5via in situ polyethylene glycol intercalation towards ultralong lifetime room/low-temperature zinc-ion batteries

Abstract

Zinc-ion batteries (ZIBs) are a main focus worldwide for their potential use in large-scale energy storage due to their abundant resources, environmental friendliness, and high safety. However, the cathode materials of ZIBs are limited, requiring a stable host structure and fast Zn²⁺ channel diffusion. Here, we develop a strategy for the intercalation of polyethylene glycol (PEG) to facilitate Zn²⁺ intercalation and to suppress the dissolution of vanadium in V₂O₅. In particular, PEG-V₂O₅ shows a high capacity of 430 mA h g⁻¹ at a current density of 0.1 A g⁻¹ as well as excellent 100 mA h g⁻¹ specific capacity after 5000 cycles, with a high current density of 10.0 A g⁻¹. A reversible capacity of 81 mA h g⁻¹ can even be achieved with a low temperature of −20 °C at a current density of 2.0 A g⁻¹ after 3500 cycles. The superior electrochemical performance comes from the intercalation of PEG molecules, which can improve kinetic transport and structural stability during the cycling process. The Zn²⁺ storage mechanism, which provides essential guidelines for the development of high-performance ZIBs, can be found through various ex situ characterization technologies and density functional density calculations.