Advanced MOF-derived carbon-based non-noble metal oxygen electrocatalyst for next-generation rechargeable Zn-air batteries

Abstract

Zn-air batteries (ZABs) are considered as one of the most prospective green electrochemical energy storage and conversion devices due to their low-cost, high-energy density, environment friendly and satisfactory safety. However, the performance of ZABs is largely limited according to the activity of oxygen electrocatalysts. Precious metal Pt-based catalysts are often used together with Ru- or Ir-based catalysts for rechargeable ZABs. However, the high price and scarce resources limit their commercialized production. Metal-organic framework (MOF) materials have been considered as a valuable candidate for cathode material of ZAB due to their suitable price, unique porous crystal structure and adjustable chemical characteristics. However, the poor electrical conductivity and insufficient chemical stability severely limit their applications in electrocatalysis. In this work, the recent development of MOF-derived carbon-based non-noble metal carbon materials as cathode catalysts for rechargeable ZABs including morphology design, chemical composition and electrochemical performance is reviewed. The catalytic mechanism of MOF-based non-noble metal carbon materials is systematically summarized, and the main points determining the electrochemical performance of MOF-derived carbon-based non-noble metal electrocatalysts are discussed in detail. Promising strategies for improving bifunctional catalytic activity are then highlighted. Finally, the sustainability research, challenges and prospects of MOF-derived carbon-based non-noble metal materials used in ZABs are proposed.