Prussian blue and its analogues for flexible electrochemical energy storage: From materials to devices

The advancement of flexible electrochemical energy storage (FEES) devices as prospective power sources for wearable and portable electronics has become a prominent subject of research. The improvement of high-capacity electrode materials presents a substantial possibility for these flexible devices. Prussian blue and its analogues (PBAs) are easily manufactured, low-cost, open in structure, stable, and can directly insert and extract large K+ and Na+ ions, making them ideal electrode materials for FEES devices. This paper offers a comprehensive examination of the crystal structure, electrochemical reaction mechanisms, and synthesis methodologies of PBAs. Furthermore, this review examines the advancements in the utilization of PBAs in FEES devices over the past few years. The future prospects and critical research directions for synthesizing PBA-based flexible electrodes and applying them to flexible energy storage devices are explored. We anticipate that this review will significantly expand our understanding of PBAs and accelerate the development of FEES.