Boosting Oxygen Electrocatalysis in CoN-CoSe2 Heterogeneous Hollow Nanocages with Engineered Build-In Electric Field for Zn–Air Batteries

The exploration of oxygen catalyst with superior behaviors in a wide temperature range is a key issue for Zn–air battery. Herein, the CoN-CoSe₂@C hollow cages with a built-in electric field (BIEF) on heterointerface are explored as the oxygen electrocatalyst for Zn–air battery (ZAB). Based on the theoretical analysis, the large work function difference (∆W_F) of CoN-CoSe₂ heterostructure propels the interfacial electron redistribution, which results in the strong BIEF and facilitates high catalytic activities. In addition, the CoN-CoSe₂ nanocrystals are embedded in the hollow carbon nanocage to fully realize its performance. The central hollow structure of the carbon based nanocages provides the facile electron/ion/mass pathways and endows fast kinetics. Taking the advantages of both the strong BIEF and the well-designed substrate, the CoN-CoSe₂@C hollow cages achieve the superior bifunctional electrocatalytic behaviors and good cycling performance even down to low-temperature such as −30 °C. Moreover, the full ZAB with CoN-CoSe₂@C hollow cage cathode shows the superior performance and high reliability in diverse working conditions. Therefore, it is a promising power source candidate for the electronics in practical applications.