Deficiency and surface engineering boosting electronic and ionic kinetics in NH4V4O10 for high-performance aqueous zinc-ion battery

Aqueous zinc-ion batteries present their unique advantages, such as cost-efficient and non-flammability for largescale energy storage. However, their widespread application is hindered by the development of cathode materials, sluggish intrinsic ion/electron kinetics, and unsatisfied structural stability. Herein, we report a high-performance NH4V4O10 cathode with oxygen vacancy (denoted as NH4V4O10-x) and reduced graphene oxide (rGO) surface modification. The oxygen vacancies enhance the Zn2+ diffusion ability and stabilize the NH4V4O10 structure. Meanwhile, the density functional theory calculations further confirm the deficiency engineering leads to high electronic conductivity, weak electrostatic interaction, and low Zn2+ diffusion barrier. In addition, the rGO surface modification provides fast electron transfer. The NH4V4O10-x @rGO delivers high capacity (391 mAh g(-1) at 1 A g(-1)), impressive rate ability (211 mAh g(-1) at the 15 A g(-1)), and stable cycle performance with 90.5% capacity retention after 2000 cycles. This work provides a reasonable strategy to design cathode materials with deficiency and surface engineering to improve the electrochemical performance of zinc-ion batteries.

Automated summary

The study presents a high-performance NH4V4O10-x @rGO cathode for aqueous zinc-ion batteries, featuring oxygen vacancies and reduced graphene oxide surface modification. This cathode shows high capacity, impressive rate ability, and stable cycle performance, providing a reasonable strategy for improving the electrochemical performance of zinc-ion batteries through deficiency and surface engineering.