An overview and future perspectives of aqueous rechargeable polyvalent ion batteries

In recent years, the rechargeable aqueous batteries have attracted great attentions among quite a few researchers because of the abundant raw materials, low cost, simple operation, safety and environmental benignity. Compared with the battery system of monovalent ions, rechargeable aqueous polyvalent ion batteries have a greater significance of research in many aspects. Although some difficulties have been encountered in the development process, plenty of efforts have been made to improve the electrochemical performance by a variety of distinct methods, such as seeking for new electrode materials, modifying surface area of materials and exploring new type of electrolytes. This review is a summary of recently reported anode materials, cathode materials and electrolytes for rechargeable aqueous polyvalent ion batteries.