Highly active PtFe alloy encapsulated in porous carbon fibers as an air-cathode catalyst for zinc–air batteries

Abstract

The rational development of effective and economical oxygen reduction reaction (ORR) catalysts is necessary for metal–air battery fabrication. Herein, a PtFe alloy embedded in porous carbon fibers (PtFe-PCFs) was fabricated through electrospinning and pyrolysis. PtFe-PCFs exhibit outstanding activity towards the ORR owing to the quick electron transmission properties of the carbon fibers, optimized activity sites of the bimetallic alloy, and the synergy effect between the alloy and the matrix. As a result, the half-wave potential in an alkaline solution is 0.853 V vs. RHE, whereas in an acidic solution, it is 0.836 V vs. RHE. When functioning as the cathode catalyst within liquid-state zinc–air batteries, PtFe-PCFs display a considerable open circuit voltage (1.49 V), excellent power density (218.05 mW cm⁻²) and long cycle stability. Additionally, when functioning in solid-state zinc–air batteries, PtFe-PCFs demonstrate a remarkable power density (128.63 mW cm⁻²) and long cycle life (14 h). This work provides perspectives into designing active sites and catalytic carriers for noble metal ORR catalysts, with broad prospects in energy conversion and storage.