A review on covalent organic frameworks for rechargeable zinc-ion batteries

In recent years, rechargeable zinc -ion batteries (ZIBs) are considered to be a promising alternative to lithium -ion batteries owing to their high safety and theoretical capacity with low cost. Nevertheless, the in-depth development of rechargeable zinc -ion batteries is restricted by a sequence of issues, such as the dissolution and structure collapse of cathode materials, the formation of by-products, severe anode corrosion, passivation, and the growth of zinc dendrites. The covalent organic frameworks (COFs) can solve the above problems to a certain extent owing to their ideal characteristics, such as rigid structure, insolubility, high porosity, and abundant active sites. COFs, as advanced materials for ZIBs, have attracted researchers' attention. In this review, we systematically summarized the synthesis methods of COFs and discussed the application of several advanced characterization technologies in COFs, which would provide a reference for the in-depth research of COFs. In addition, we elucidated the use of COFs as cathode materials and anode protective layers in rechargeable ZIBs. Finally, we discussed the challenges and solutions in the development of COF materials, which would provide constructive insights into the future direction of COFs.