Recent Developments and Future Prospects for Zinc-Ion Hybrid Capacitors: a Review

The design and development of advanced energy storage systems with both high energy/power densities and long cycling life have long been a research hotspot. Zinc-ion hybrid capacitors (ZICs) are regarded as emerging and highly promising candidates, which originates from the combined advantages of zinc-ion batteries (ZIBs) with large energy density and supercapacitors (SCs) with exceptional power density and cycle stability. This critical review comprehensively and systematically summarizes the fundamentals and recent advances of ZICs, including their compositions, two types of energy storage mechanisms, advantages and disadvantages of ZICs as well as their electrode materials, electrolytes and new types of devices. Moreover, the present challenges and future research directions of ZICs are proposed, which need further research. This review is expected to provide good guidance for the design and exploitation of high-performance ZICs to realize their potential practical applications.