High-efficient CoPt/activated functional carbon catalyst for Li-O2batteries

The rational design and synthesis of highly-efficient cathode catalysts are of importance to high-performance lithium-oxygen batteries (LOBs). In this work, We use crab shell waste as a carbon source through carbonization, activation, and sol-gel method to synthesize activated functional carbon (AFC) and fabricate CoPt/AFC catalyst for Li-O2batteries. The as-prepared AFC possesses abundant hydroxyl (OH‒) and amino (NH2‒) groups as the link bridge for enhancing the metal-support interaction. Revealed by the density functional theory calculations, the tuned adsorption for intermediates and reduced overpotentials for both oxygen reduction and evolution reactions (ORR and OER) are achieved on such the composite structure. Experimentally, CoPt nanoparticles are evenly distributed on the surface of OH‒ and NH2‒ functionalized porous carbon through the sol-gel method. The abundant pore structures in the resultant catalyst (CoPt/AFC) can provide sufficient room for depositing discharge products. Moreover, the side reactions are effectively suppressed, as evidenced by the in-situ Raman spectra. As a result, the LOBs with the CoPt/AFC cathode present excellent electrochemical performances with a high discharge specific capacity of 8.25 mAh cm−2, a low overpotential of 0.47 V, and good cycling stability of 156 cycles.