材料科学
电化学
电池(电)
钴
氧化钴
石墨烯
电流密度
氧化物
双功能
电极
化学工程
催化作用
无机化学
冶金
纳米技术
化学
功率(物理)
物理化学
工程类
物理
量子力学
生物化学
作者
Wei Jian Sim,Mai Thanh Nguyen,Zixuan Huang,Soorathep Kheawhom,Chularat Wattanakit,Tetsu Yonezawa
出处
期刊:Nanoscale
[The Royal Society of Chemistry]
日期:2022-01-01
卷期号:14 (22): 8012-8022
被引量:13
摘要
Iron-cobalt (FeCo) oxides dispersed on reduced graphene oxide (rGO) were synthesized from nitrate precursors at loading levels from 10 wt% to 60 wt%. These catalysts were tested in lab-scale zinc-air batteries (ZABs) at a high current density of 100 mA cm-2 of the cathode area for the first time, cycling between 60 min of discharging and 60 min of charging. The optimum loading level for the best ZAB cycling performance was found to be 40 wt%, at which CoFe2O4 and CoO nanocrystals were detected. A discharge capacity of at least 90% was maintained for about 60 cycles with FeCo 40 wt%, demonstrating superior stability over amorphous FeCo oxides with FeCo 10 wt% despite similar performance at electrochemical tests. At a high current density of 100 mA cm-2, OER catalytic activity was found to be the limiting factor in ZAB's cyclability. The discrepancies between the ORR/OER catalytic activities by electrochemical and battery cycling test results highlight the role and importance of rGO in improving electrical conductivity and activation of metal oxide electrocatalysts under high current density conditions. The difference of battery cycling test results from traditional electrochemical test results suggests that electrochemical tests conducted at low current densities may be inadequate in predicting practical battery cycling performance.
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