Waste Lithium Ion Battery Evolves into Heteroatom Doped Carbon as Oxygen Reduction Electrocatalyst for Aqueous Al-Air Batteries.

Abstract

Carbon based electrocatalysts prepared by recycling waste power batteries can not only realize the new utilization of waste energy materials, but also obtain cheap and efficient oxygen reduction electrocatalyst for metal-air battery. Based on the cathode carbon of waste LiFePO4 batteries, nitrogen doped carbon based catalyst NC-1000 is prepared by simple pyrolysis, acid dissolution of LiFePO4 and high temperature heteroatom doping. The catalyst is characterized by scanning electron microscope, transmission electron microscope and Raman spectrum, and the electrochemical performances of the catalyst and Al-air battery were tested. The results show that carbon based electrocatalyst NC-1000 is rich in structural defects and embedded with trace metal oxides. Compared with commercial 20 wt% Pt/C, it has higher electrocatalytic activity and faster kinetic with a half-wave potential of 0.828 V vs. RHE and the Tafel slope of 70.7 mV dec-1 . In addition, assembled into Al-air battery, the open circuit potential can reach 1.57 V along with the high power density of 141 mW cm-2 at 200 mA cm-2 . The discharge specific capacity at higher current of up to 100 mA cm-2 is even better than the commercial Pt/C. This study can not only improve the economic value of waste power batteries, but also obtain high-performance ORR electrocatalyst, which will greatly promote the commercial development of Al-air batteries.