NiCo-PBA-Derived Hollow Co–C–N-Doped NiS Nanocages as High-Performance Cathode Materials for Aqueous Zinc-Ion Batteries

Abstract

Aqueous zinc-ion batteries (AZIBs) have emerged as a promising candidate for next-generation energy storage systems due to their low cost, high safety, and environmental benignity. Nevertheless, the inherent drawbacks of zinc-ion battery cathode materials, including insufficient active sites and unsatisfactory cycling stability, have significantly hindered their practical industrial applications. In this study, hollow Co–C–N-doped NiS nanocages (CoCN–NiS) were fabricated using a nickel–cobalt Prussian blue analogue (NiCo-PBA) nanocube template strategy followed by Na2S etching. The effects of template regulation and reaction temperature on the microstructure, crystal structure, and chemical bonds of these nanocages were investigated. The unique hollow cubic structure provides abundant active sites, shortens ion transport pathways, and alleviates volume expansion during cycling. Consequently, CoCN–NiS exhibits excellent electrochemical performance. A specific discharge capacity of 162 mAh g–1 was achieved at 0.05 A g–1, significantly superior to that of NiCo-PBA (101 mAh g–1). Moreover, after 800 cycles at 0.2 A g–1, CoCN–NiS has a capacity retention of 69.1% and a Coulombic efficiency approaching 100%. The high-performance CoCN–NiS fabricated in this work demonstrates promising application prospects as cathode candidates for aqueous zinc batteries, offering a novel strategy for the development of high-efficiency and long-cycling cathode materials.