Ultraviolet-Assisted Construction of Low-Pt-Loaded Mxene Catalysts for High-Performance Li−O2 Batteries

Abstract

Achieving high electrocatalytic activity with low amount of noble metals is critical for improving the performance and reducing the cost of Li‒O 2 batteries. Herein we describe an ultraviolet-assisted synthesis method of preparing highly active and superb stable MXene-based electrocatalysts containing low Pt content. The obtained electrocatalysts feature homogenous Pt nanocrystals embedded within multilayer Ti 3 C 2 MXene (Pt‒Ti 3 C 2 ). Because of the improvement on electrical and catalytic properties and structural stability, this catalyst design enables promising electrochemical performance. Notably, at an ultralow Pt loading of 0.01 mg cm −2 cathode, the catalyst exhibits a high discharge capacity of 14769 mAh/g Pt‒Ti3C2 , a low charge overpotential of 0.32 V, and excellent cycle performance over 100 cycles. Systematic studies reveal the relevancy between electrocatalytic performance and chemical microstructure, whereas the stable Pt‒Ti chemisorption facilitates the synergistic catalysis between Pt nanocrystals over multilayer Ti 3 C 2 substrates. Density functional theory reveals mechanistic insights into electrocatalytic effect on the reduction of charge overpotential, whereas the mild interaction between Pt‒Ti 3 C 2 and Li 2 O 2 monomer enables low charge overpotential.

Keywords: noble metal, MXene, Low-loading, cathode catalyst, Li‒O2 batteries