Facile Fabrication of Ag Nanocrystals Encapsulated in Nitrogen‐doped Fibrous Carbon as an Efficient Catalyst for Lithium Oxygen Batteries
Lili Liu, Tianyi Ma, Weiwei Fang, Yuqing Liu, Kostantin Konstantinov, Jiazhao Wang, Huan Liu
Abstract
A facile synthesis of Ag nanocrystals encapsulated in nitrogen‐doped carbon fiber (NCF) is proposed, based on the simultaneous reaction between pyrrole and Ag + ions in an aqueous solvent followed by a heat treatment. The as‐prepared Ag/NCF demonstrated superior catalytic behavior toward ORR and OER. Besides improved cycling stability, a much lower discharge/charge gap of 0.89 V (vs Li/Li + ) compared with 1.38 V for NCF cathode with a fixed capacity of 500 mAh g −1 was obtained in lithium oxygen batteries. The introduction of Ag crystals into NCF facilitates the oxygen reduction reaction/oxygen evolution reaction kinetics. X‐ray diffraction analysis coupled with Raman spectroscopy confirmed that Ag/NCF cathode could reversibly catalyze Li 2 O 2 formation and decomposition. The NCF matrix offers a conductive network to realize rapid mass transfer and the encapsulated Ag nanocrystals supplied effective catalytic active sites. The combined action between both contributes to the superior electrocatalytic performance.