Thermally Labile Organic-Soluble Heterometal Diorganophosphate-Derived Efficient Electrocatalysts for the Oxygen Evolution Reaction

Heterometal phosphates are burgeoning electrocatalysts and cathode materials in energy storage and conversion devices. In this work, we demonstrate a novel and clean synthetic route for substoichiometric lithium-deficient metastable Cmcm-Li0.65(7)Co1.16(2)PO4 (Li-Co-P-HEX) and metaphosphate P212121-LiCo(PO3)3 (Li-Co-P-BT), starting from the same starting material [LiCo(dtbp)3] (dtbp = di-tert-butyl phosphate) through a thermolytic single-source precursor approach. The heterometal organophosphate [LiCo(dtbp)3] decomposed into different phases of inorganic heterometal phosphates by employing a solution and solid-state thermal treatment. The solution-processed Li-deficient orthophosphate exhibits superior oxygen evolution reaction activity, delivering a current density of 10 mA cm–2 at an overpotential of 294 mV, outperforming other reported lithium–cobalt phosphates for water oxidation. The enhanced performance of the Cmcm-Li0.65(7)Co1.16(2)PO4 as an electrocatalyst elucidates the synergistic effect generated by the structure, composition, and morphology.