A Review on the Features and Progress of Dual-Ion Batteries

Despite the wide application of lithium-ion batteries in portable electronic devices and electric vehicles, the demand for new battery systems with the merits of high voltage, environmental friendliness, safety, and cost efficiency is still quite urgent. This perspective focuses on dual-ion batteries (DIBs), in which, both the cations and anions are involved in the battery reaction. An anion's intercalation/deintercalation process on the cathode side allows the DIBs to operate at high voltages, which is favorable for enhanced energy density. However, electrolytes with a wide electrochemical window and suitable anion-intercalation materials with highly reversible capacities should be developed. The progress of research into stable organic electrolytes, ionic liquids, and their effects on the electrochemical performances of DIBs are first discussed. Thereafter, the anion-host materials including graphitic materials, organic materials, and their working mechanisms are discussed in detail. In addition, recently emerging DIB systems with high-capacity anodes, or sodium-, potassium-ion involved battery reactions are also reviewed. The authors' recent work, demonstrating a generalized DIB construction using metal foil as both current collector and alloying anode material, which is successfully extended into lithium-, sodium-, and potassium-based DIBs, is also discussed.