Carbon-Layer-Protected CoP/Carbon Nanosheets as Highly Durable Bifunctional Electrocatalysts for Rechargeable Zinc–Air Batteries
Maosong Liu, Xianhe Lv, Zhiqiang Mi, Shanliang Chen, Jianhua Li, Jiqing Wu, Tao Sun, Long Zhang, Jianming Zhang
Abstract
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.