Optimization strategies for high performance zinc-ion hybrid supercapacitors: Advances in materials, interfaces and devices

Abstract

Zinc-ion hybrid supercapacitors (ZIHSs) have become a popular candidate for the next generation of energy storage systems due to their high safety, low cost, environmental friendliness, and high power density-high energy density balance. However, at present, ZIHSs still face low energy density, insufficient understanding of the electrochemical energy storage mechanism, and side reactions and stability issues of zinc anodes. Considerable efforts have been invested and many key advances have been made to address these practical application challenges in the recent years. This work analyzes the research advancements in zinc-ion supercapacitors, emphasizing their energy storage mechanisms, key material designs, and performance optimization strategies. First, the device composition and energy storage mechanisms of ZIHSs are introduced. Subsequently, methods to enhance the capacity and cycling stability, as well as improve the rate performance, are evaluated in terms of anode materials design, zinc anode modification strategies (involving interfacial engineering and structural design), and electrolyte optimization approaches (covering aqueous, quasi-solid-state, and multifunctional additives). Furthermore, the generation mechanisms of zinc dendrites and HER, along with corresponding interface modification strategies, are systematized. Novel optimization frameworks involving electrode materials are also presented. Finally, the opportunities and challenges confronting this field are discussed, and potential future research directions are outlined. Overall, this review provides novel perspectives and actionable recommendations for the advancement of ZIHSs.