A leaf-like porous N-doped carbon structure embedded with CoS2 nanoparticles self-supported on carbon fiber paper as a cathode in flexible zinc–air batteries

Abstract

Developing new forms of flexible zinc–air (Zn–air) batteries is crucial to economic growth. Nevertheless, the absence of an oxygen evolution reaction catalyst with high catalytic efficiency and low-cost causes instability of Zn–air battery cycling and economic unviability, respectively. In this paper, a leaf-like N-doped carbon structure with CoS₂ nanoparticles self-supported on carbon fiber paper (CoS₂-CZ@CFP) was developed as an air electrode for Zn–air batteries, which not only uses nonprecious metal elements, but also has a self-supporting configuration, enhancing the contact between the catalyst and electrode while facilitating the transfer of electrons. Sulfur as the source gas was introduced into Co-doped metal–organic skeletons (Co-ZIFs) anchored on carbon fiber paper (CFP) for in situ vulcanizing transition metal Co, which successfully ensures the uniform distribution of sulfide particles in the carbon matrix, hence enriching active catalyst sites. The CoS₂-CZ@CFP demonstrated an overpotential of 1.611 V at J = 50 mA cm⁻², superior to RuO₂@CFP (1.814 V). A Zn–air battery fabricated using the synthesized CoS₂-CZ@CFP exhibited an extended life cycle of 117 h. This research paves the way for a novel method of designing self-supporting configurations of sulfides and carbon matrix composites as promising air electrodes applicable to Zn–air batteries.