Rationalizing the Anion Storage in Cathodes for Optimum Dual-Ion Batteries: State of the Art and the Prospect

For a dual-ion battery (DIB) configuration, both anions and cations contribute to the capacity. A high anion intercalation operating potential corresponds to a wide working window, which leads to both high energy density and power density for DIBs. Because orderly layered structures and proper interlayer space can accommodate anion intercalation, graphite was widely used as the cathode for DIBs. However, the relatively low discharge capacity and poor cycling stability of graphite cathode limit the practical application of DIBs. Therefore, it is crucial for anion storage to construct a robust and stable cathode. On the basis of the delicate structural design of electrodes, we summarize the main factors affecting the anion storage and the strategies for improving performance of DIBs, which will provide far-reaching significance for improving the capacity and stability of DIBs.