Recent progress and challenges of carbon materials for Zn-ion hybrid supercapacitors

Zinc-ion hybrid supercapacitors (ZHSCs) have garnered increasing attention as promising energy storage devices in recent years, as they combine the advantages of high-energy Zn-ion batteries and high-power supercapacitors. However, the development of ZHSCs is still in its infancy and there are many bottlenecks to overcome. In particular, the challenge induced by the limited ion adsorption capability of carbon-positive electrodes severely restricts the energy density of ZHSCs. Therefore, it has become a key issue to design novel carbon-positive electrodes that enable high energy density yet do not deteriorate the intrinsic power capability and long-term durability. This study focuses on recent achievements in synthesis, morphology, and electrochemical performance of various carbon materials applied in ZHSCs. The modification strategies to optimize their electrochemical performance are briefly summarized. In addition, current challenges and future opportunities in this field are also outlined. This review will be beneficial to provide an organized framework for the research systems of carbon-positive electrodes and develop novel ZHSCs with high energy density.