The rapid-growing demands for lithium-ion batteries (LIBs) have raised concerns over lithium's scarcity as well as the scarcity of other materials and components used in LIBs. Tremendous efforts have been dedicated to investigating alternative technologies. Dual-ion batteries (DIBs) represent an emerging battery technology with an attractive future such as high working voltage and a high-power density enabled by a “nonrocking chair” operation. Research in DIBs is still at an early stage. The energy density of DIBs remains a challenge to solve, especially in comparison with LIBs. This review highlights current challenges in the research on DIBs from different aspects, including undesirable graphite exfoliation during ions intercalation, limited choices of cathode materials, unstable electrolytes, battery safety, and discusses potential strategies for addressing these challenges. Perspectives for exploring the next-generation DIBs with high energy density are also provided.
