Recent progress of Prussian blue analogues as cathode materials for nonaqueous sodium-ion batteries

The urgent market demand of energy storage and conversion has promoted the extensive investigations of coordination polymers. As a kind of simple cyano-bridged coordination polymers, Prussian blue (PB) and Prussian blue analogues (PBAs) have been considered as the promising cathode materials in sodium-ion batteries (SIBs) because of their 3D open framework, adjustable structure and chemical composition. Currently, the fundamental research and commercial exploration of PB and PBAs in nonaqueous SIBs are making robust progress. This review summarizes the recent advance and systematical cognition of PB and PBAs, mainly discussing the chemical composition and structure, material synthesis, modification strategy and sodium storage mechanism in nonaqueous SIBs. The structure-properties relationship of PB and PBAs is deeply revealed from the respects of bulk phase and interfacial stability. Moreover, the issues and perspectives are also analyzed to promote the future scientific research and commercial application for PB and PBAs cathode in nonaqueous SIBs.