Modulating the Energy Barrier via the Synergism of Cu3P and CoP to Accelerate Kinetics for Bolstering Oxygen Electrocatalysis in Zn-Air Batteries.

ABSTRACT

Modulating the energy barrier of reaction intermediates to surmount sluggish kinetics is an utterly intriguing strategy for amplifying the oxygen reduction reaction. Herein, a Cu3P/CoP hybrid is incorporated on hollow porous N-doped carbon nanospheres via dopamine self-polymerization and high-temperature treatment. The resultant Cu3P/CoP@NC showcases a favorable mass activity of 4.41 mA mg-1 and a kinetic current density of 2.38 mA cm-2. Strikingly, the catalyst endows the aqueous Zn-air battery (ZAB) with a large power density of 209.0 mW cm-2, superb cyclability over 317 h, and promising application prospects in flexible ZAB. Theoretical simulations reveal that Cu functions as a modulator to modify the free energy of intermediates and adsorbs the O2 on the Co sites, hence rushing the reaction kinetics. The open and hydrophilic hollow spherical mesoporous structure provides unimpeded channels for reactant diffusion and electrolyte penetration, whereas the exposed inner and outer surfaces can confer a plethora of accessible actives sites. This research establishes a feasible design concept to tune catalytic activity for non-noble metal materials by construction of a rational nanoframework.