Engineering Interface and Oxygen Vacancies of Ni_xCo_1–xSe₂ to Boost Oxygen Catalysis for Flexible Zn–Air Batteries

Exploring efficient bifunctional oxygen electrocatalysts is a critical element for developing high-power-density metal–air batteries. Here, we propose an interface and oxygen vacancy engineering strategy to integrate subtle lattice distortions, oxygen vacancies, and nanopores on the surface of NixCo1–xSe2–O interface nanocrystals, which exhibit efficient bifunctional catalytic performances for oxygen evolution and reduction. The results from X-ray absorption spectroscopy and electron spin resonance spectroscopy demonstrate that the defect structure can enlarge the number of active sites for electrocatalytic performances. Flexible Zn–air battery using NixCo1–xSe2–O as a cathode displays large specific capacity and remarkable stability even after twisting at any angle, thus showing potential for wearable and portable electronic device application. The implementation of our method provides a powerful strategy for preparing advanced catalysts for energy utilization.