Abstract

Highly efficient and environmentally friendly multifunctional electrode materials for application in super -capacitors to electrocatalysis are important for advances in the future of electrical energy storage and green hydrogen production. This work reports a simple growth strategy to obtain hierarchical P(Ni, Co, Fe) modified electrodes by phosphating a core/shell composite of nickel-cobalt (NiCo) Prussian blue analogues fabricated through an in situ self-sacrificial growth process. Due to the unique microstructure, abundant surface-active sites, and enhanced interfacial conductivity, the hybrid electrode exhibits specific capacitance as high as 1125.8 F g-1 (3.7 F cm-2) at 2 mA cm-2, excellent rate capability and improved cycling stability (97.1% retention capacitance after 5000 cycles at 50 mA cm-2 and 89.9% after continuous 5000 cycles at 100 mA cm-2). Furthermore, the hybrid structure shows excellent oxygen evolution reaction performance with an overpotential of 252 mV at 100 mA cm-2 and 283 mV at 300 mA cm-2, with a low Tafel slope of 68 mV dec- 1, and overall water splitting abilities with a cell voltage of 1.55 V at 100 mA cm-2. This work provides insights into the design of next -generation high-performance multifunctional electrode materials by controlling the surface/interface of multi -component structures for enhancing their properties.