ZIF-67 derived hierarchical hollow sphere-like CoNiFe phosphide for enhanced performances in oxygen evolution reaction and energy storage

Transition metal phosphides have attracted much research interests in energy conversion and storage as a result of their enhanced physiochemical properties. Here, we report the successful synthesis of tri-metal (CoNiFe) based porous hierarchical hollow sphere-like phosphides through a simple solvothermal process and a low temperature phosphorization process. The special nanostructure endows the phosphide electrocatalyst a rough surface, which in turn provides much more active sites and defects to enhance the performances in oxygen evolution reaction (OER) and lithium storage. The synergetic effects among the metal elements and combination with the advantages of metal phosphides contribute mostly to the enhanced performances. The optimized electrocatalyst exhibits a low overpotential of 279 mV at 10 mA cm⁻² and a Tafel slope of 62.9 mV dec⁻¹ for OER. Benefiting from the structural and compositional advantages of the phosphide catalyst, it also shows good stability and high capacity in lithium storage.