阴极
材料科学
氧化还原
电化学
电解质
锂(药物)
化学工程
电池(电)
过电位
储能
纳米技术
电极
化学
物理化学
医学
物理
工程类
内分泌学
功率(物理)
冶金
量子力学
作者
Yue Wang,Lina Song,Yifeng Wang,Fēi Li,Xiaoxue Wang,Huanfeng Wang,Ji‐Jing Xu
标识
DOI:10.1016/j.ensm.2021.11.038
摘要
Soluble redox mediators (RMs) with favorable contact interface are considered to be an effective approach for high efficient lithium-oxygen (Li-O2) batteries. However, the shuttling effect of oxidized RMs from the cathode would lead to the degradation of the RMs’ functionality and poor cycling stability. Herein, TEMPO was anchored into three-dimensional porous [email protected]/NF conductive substrate ([email protected]@PPy-TEMPO/NF) and directly utilized as a self-supporting cathode for Li-O2 battery. This novel cathode serves multiple functions as redox mediator, abundant reaction center for lithium ion, as well as electron conduction matrix. The battery perform with a high discharge specific capacity of 6.9 mAh cm−2 and a low overpotential of 0.6 V similar with 4-OH-TEMPO in the electrolyte. The detailed catalysis mechanism of the immobilized TEMPO in improving the electrochemical performance has also been studied. During discharging, the cation-π effect between the conductive polypyrrole and lithium ions helps to realize the "isomorphic growth" of Li2O2. During charging, the TEMPO-immobilized electrochemical oxidation to TEMPO+ provides more direct contact with the discharge products, resulting in rapid chemical oxidation of Li2O2. The ingenious design and in-depth mechanism study provide a new avenue to address the shuttle effect of RMs and design an advanced cathode for Li-O2 batteries.
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