Micro-meso-macroporous FeCo-N-C derived from hierarchical bimetallic FeCo-ZIFs as cathode catalysts for enhanced Li-O2 batteries performance

Publication date: Available online 24 March 2019Source: Journal of Energy ChemistryAuthor(s): Fufang Chao, Baoxing Wang, Jiaojiao Ren, Yingwei Lu, Wenrui Zhang, Xizhang Wang, Lin Cheng, Yongbing Lou, Jinxi ChenAbstractDeveloping bifunctional catalysts that increase both the OER and ORR kinetics and transport reactants with high efficiency is desirable. Herein, micro-meso-macroporous FeCo-N-C-X (denoted as “M-FeCo-N-C-X”, X represents Fe/Co molar ratio in bimetallic zeolite imidazole frameworks FeCo-ZIFs) catalysts derived from hierarchical M-FeCo-ZIFs-X was prepared. The micropores in M-FeCo-N-C-X have strong capability in O2 capture as well as dictate the nucleation and early-stage deposition of Li2O2, the mesopores provided a channel for the electrolyte wetting, and the macroporous structure promoted more available active sites when used as cathode for Li-O2 batteries. More importantly, M-FeCo-N-C-0.2 based cathode showed a high initial capacity (18,750 mAh g−1@0.1 A g−1), good rate capability (7,900 mAh g−1@0.5 A g−1), and cycle stability up to 192 cycles. Interestingly, the FeCo-N-C-0.2 without macropores suffered relatively poorer stability with only 75 cycles, although its discharge capacity was still as high as 17,200 mAh g−1(@0.1 A g−1). The excellent performance attributed to the synergistic contribution of homogeneous Fe, Co nanoparticles and N co-doping carbon frameworks with special micro-meso-macroporous structure. The results showed that hierarch...
Source: Journal of Energy Chemistry - Category: Chemistry Source Type: research