Recent progress on the heteroatom-doped carbon cathode for zinc ion hybrid capacitors

Under the double carbon background of "carbon peak" and "carbon neutrality, the use of energy storage and conversion devices (ESCDs) becomes more and more important. As one of the ESCDs, zinc ion hybrid capacitors (ZIHCs) are considered as the most promising candidate on account of their virtues of excellent safety, environmentally friendly and superior physicochemical stability, which combined the merits of zinc-ion batteries with high energy density and supercapacitors with fast charging rate and long cycle life. This review systematically generalizes the history of hybrid capacitors and the working mechanism of ZIHCs. An investigation of the preparation process, structural characteristics, electrochemical properties of heteroatom-doped carbon materials, as well as the effect of various hetero-atoms on the mechanism of zinc ion storage, is described in detail in this review. Additionally, the current challenges and future investigable directions of ZIHCs are elucidated. Through studying the compact of heteroatoms on the storage mechanism and performance of zinc ions, this review should provide theoretical guidance for the application of ZIHCs.