Prussian Blue Analogue-Based Nanowires as Cathode Materials for Aqueous Aluminum-Ion Storage

Multivalent metal aqueous rechargeable batteries have great prospects in energy storage systems due to being environmentally friendly and having moderate cost. At present, the main research object of trivalent metals is aqueous aluminum-ion batteries (AAIBs). However, the high charge carried by Al 3+ ions results in strong electrostatic interactions during intercalation and deintercalation of the host material. The host material structure is unstable, resulting in poor cycling performance, slow ion diffusion kinetics, and a low power output. Prussian blue analogues (PBAs) have become a promising electrode material for aqueous rechargeable batteries due to their high stability. Herein, we synthesized one-dimensional (1D) CoPBA as an innovative and high-performance cathode material for the AAIBs is reported. As a result of the unique anisotropic properties, 1D-CoPBA can provide fast axial electron transfer and short ion diffusion paths, which results in lower resistance and better contact with the electrolyte. The 1D-CoPBA cathode has a high initial discharge capacity of 100.1 mAh g –1 at 50 mA g –1 and outstanding capacity retention of 87% after 2000 cycles at 1000 mA g –1, along with an efficiency of around 100%. Assembled with 3,4,9,10-perylene tetracarboxylate diimide (PTCDI) anodes, the full battery can also deliver impressive electrochemical properties. This study provides a way to reform PBAs for high-performance cathode materials in aqueous multivalent ion batteries.