Separators in aqueous zinc-ion batteries: Interfacial chemistry and optimization strategies

Aqueous zinc-ion batteries (ZIBs) with the unique merits including environmental friendliness, low cost and intrinsic safety, exhibit great potential in large-scale energy storage devices. Nevertheless, there are still many scientific and technical issues required to be revealed, especially the fundamental sciences of the interfacial chemistry, which can profoundly affect the electrochemical performance of aqueous ZIBs. Recently, separator modification has gained popularity as effective ways to improve ZIBs performance, but the work on the comprehensive discussion and perspectives in developing zinc-ion separators is still relatively lacking. Therefore, it is important to systematically understand the ionic electrochemical behaviors by separator manipulation, which will guide the fundamental research and further practical application. In this review, a systematic summary with regard to the basic characteristics of separators, the various ionic electrochemical behaviors at electrode/electrolyte interfaces (EEI) and optimization strategies, has been put forward. The final section proposes the practical considerations and future perspectives to manipulate the zinc-ion separators.