Carbon-Layer-Protected CoP/Carbon Nanosheets as Highly Durable Bifunctional Electrocatalysts for Rechargeable Zinc–Air Batteries

The commercialization of rechargeable Zn–air batteries (ZABs) relies heavily on the development of cost-effective and highly durable bifunctional electrocatalysts that can promote both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Transition-metal phosphides-based carbon (TMPs/C) composites have recently been acknowledged as highly efficient bifunctional catalysts, yet the successful construction of TMPs/C still remains a formidable challenge. Here, we report a carbon dots (CDs)-assisted approach to efficiently fabricate CoP/C nanocomposites with fine microstructures acting as a highly active and durable bifunctional electrocatalyst for both ORR and OER. The CDs act as a stable platform to adsorb and immobilize Co precursors, obstructing the coalescence of small CoP particles during pyrolysis and eventually ensuring the formation of a fine TMPs/C microstructure, where carbon-encapsulated dense CoP particles are uniformly distributed on carbon nanosheets (CoP@C/CNSs). The ZAB assembled using the CoP@C/CNSs as electrode electrocatalysts expresses excellent performance with a high power density of 180.1 mW cm –2, a relatively high specific capacity (916 mA h g –1 ), and a long cycling life of over 80 h at 10 mA cm –2 . The catalyst with such a configuration is anticipated to provide a practical solution for the production and storage of clean energy.