Recent progress and perspectives on dual-ion batteries

Lithium-ion batteries (LIBs) have gradually approached the upper limit of capacity, and yet, they are still far from fulfilling the ambitious targets required to meet the grid's storage needs due to their unsatisfactory cycling stability, limited energy density, high cost, and environmental concerns. Dual-ion batteries (DIBs) with non-aqueous electrolyte, as potential alternatives to LIBs in smart-grid application, have attracted much attention in recent years. DIBs were initially known as dual-graphite batteries, where both anions and cations separately intercalate into graphite electrodes during the charge-discharge process. The anion intercalation into the host material enables DIBs in non-aqueous electrolyte to feature a high operating voltage, which also contributes to their enhanced energy density. Moreover, the use of low-cost and “green” raw electrode materials in DIBs offers huge advantages compared to LIBs, in terms of environmental protection by avoiding problems from the disposal of discarded batteries. In this contribution, we comprehensively summarize the recent progress on DIBs with aqueous and non-aqueous electrolytes as well as the limitations and challenges of current DIB technology. Furthermore, some suggestions that might help to address the current challenges of DIB technology are proposed for future work.