Aqueous proton batteries (APBs) are increasingly recognized as promising energy storage devices owing to their high safety, environmental friendliness, and fast kinetics. Copper hexacyanoferrate (CuHCF), with its open framework structure and interconnected proton transport channels, is regarded as a promising cathode material for APBs. However, its practical application is hindered by limited active sites and structural distortion induced by the Jahn–Teller effect. To address these issues, this study employs a Co 2+ doping strategy to successfully synthesize a CuCoHCF-1 material with high specific capacity and excellent structural stability. The incorporation of Co 2+ optimizes the local coordination environment by forming stronger Co-N bonds, effectively suppressing lattice distortion. Meanwhile, it modulates the intramolecular charge distribution, activating more Fe sites for redox reactions. Benefiting from the synergistic enhancement of structural stability and electrochemical activity, the CuCoHCF-1 cathode exhibits superior rate performance, a high specific discharge capacity (84.4 mAh·g –1 at 0.1 A·g –1 ), and remarkable cycling stability (93.1% capacity retention after 40,000 cycles at 5 A·g –1 ). This study provides an effective strategy for designing high-performance cathode materials for APBs through multifunctional cation doping.
Wang et al. (Tue,) studied this question.