Cathode materials for aqueous zinc-ion batteries and prospect of self-supporting electrodes: A review

Aqueous zinc-ion batteries (AZIBs) are considered to be very promising new secondary batteries because of their safe, non-toxic, environmentally friendly and low cost advantages, their energy storage capacity and cycling performance are based on cathode materials. Here we mainly introduce manganese-based and vanadium-based materials, the widely recognized energy storage mechanism and some modification methods that have been intensively studied. Then we introduce the binder-free self-supporting electrode, which has been rarely summarized before. Its active material is directly grown on the collector, the preparation of self-supported electrodes by plasma electrolytic oxidation (PEO) on Ti foil has been successfully used for lithium-ion batteries. With appropriate regulation, the PEO film should also be successfully used in AZIBs.