Prussian blue and its analogues for aqueous energy storage: From fundamentals to advanced devices

Aqueous energy storage technologies promise grand advantages in the field of grid-scale power stations due to their attractive characteristics of low cost, safe operation, and environmental benignity. Nevertheless, the complex energy storage mechanism in aqueous media expresses rigid requirements for the host materials. As a kind of metal-organic coordination materials, Prussian blue (PB) and its analogues (PBAs) have been drawing immense research activities because of their open framework desirable for reversible insertion/extraction of various guest cations. In this review, the fundamental chemistry and electrochemistry of PB/PBAs are firstly discussed. Subsequent emphasis is put on the discussion of effective design strategies toward specific issues. Recent advances of PB/PBAs in different aqueous batteries and supercapacitors are then substantially scrutinized by correlating the electrochemical properties with the structural and compositional characteristics. To conclude, the ongoing challenges and critical perspectives for future development of PB/PBAs toward practical aqueous energy storage devices are provided.