Stable High-Voltage Aqueous Zinc Battery Based on Carbon-Coated NaVPO4F Cathode

Rechargeable aqueous zinc-ion batteries (AZBs) are potentially considered as potential alternatives for large-scale stationary energy storage systems by taking advantage of their easy operating condition, low cost, safety, and environmental friendliness. Herein, we construct high-voltage and stable AZBs with a carbon-coated NaVPO4F cathode. A 15 M NaClO4 + 1 M ZnCF3SO3 solution enables the Na+ and Zn2+ co-insertion mechanism, and the high concentration suppresses vanadium dissolution with long-term stability. The carbon-coated NaVPO4F cathode displays a superior rate capability and exhibits a reversible capacity of 87.4 mAh g(-1) and a capacity retention of 94.5% over 400 cycles at 0.1 A g(-1). Even at a higher current density of 1 A g(-1), it demonstrates an ultralong lifetime of over 4000 cycles with a capacity retention of 89.3%. The highly reversible structural transformation that occurs during the electrochemical insertion/extraction process is evidenced by a series of ex situ XRD, Raman, and XPS analyses.

Automated summary

In this study, high-voltage and stable AZBs were constructed using a carbon-coated NaVPO4F cathode, which showed superior rate capability and long lifetime. The high concentration NaClO4 and ZnCF3SO3 solution effectively suppressed vanadium dissolution, leading to long-term stability in the battery system.