Liu Xiao, Zhang Peng, Liu Liangliang, Feng Jianwen, He Xiaofeng, Song Xiaosheng, Han Qing, Wang Hua, Peng Zhangquan, Zhao Yong
Key Lab for Special Functional Materials of Ministry of Education; National and Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology; School of Materials Science and Engineering; Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng, Henan 475004, P. R. China.
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China.
ACS Appl Mater Interfaces. 2020 Mar 4;12(9):10607-10615. doi: 10.1021/acsami.0c01105. Epub 2020 Feb 21.
Aprotic lithium-oxygen (Li-O) batteries with an ultrahigh theoretical energy density have great potential in rechargeable power supply, while their application still faces several challenges, especially poor cycle stability. To solve the problems, one of the effective strategies is to inhibit the generation of the LiO intermediate produced via a surface-mediated oxygen reduction reaction (ORR) pathway, which is an important species inducing byproduct generation and low cell cyclic stability. Herein, a series of quinones and solid materials serve as the solution-mediated and surface-mediated ORR catalysts, and it was found that the generation of LiO and byproducts from solid catalysts was inhibited by quinones. Among the studied quinones, benzo[1,2-:4,5-']dithiophene-4,8-dione, a quinone molecule with the advantage of a highly symmetrical planar and conjugated structure and without α-H, exhibits high redox potential, diffusion coefficient, and electrochemical stability, and consequently the best ORR activities and the capability to inhibit byproduct generation. It indicated that the increase of the solution-mediated ORR pathway plays an important role in restraining the discharging side reaction, substantially improving cell cycle stability and capacity. This study provides the theoretical and experimental basis for better understanding the ORR process of Li-O batteries.
具有超高理论能量密度的非质子锂氧（Li-O）电池在可充电电源方面具有巨大潜力，但其应用仍面临若干挑战，尤其是循环稳定性差。为了解决这些问题，一种有效的策略是抑制通过表面介导的氧还原反应（ORR）途径产生的LiO中间体的生成，LiO是导致副产物生成和电池循环稳定性低的重要物质。在此，一系列醌类和固体材料用作溶液介导和表面介导的ORR催化剂，并且发现醌类抑制了固体催化剂中LiO和副产物的生成。在所研究的醌类中，苯并[1,2-:4,5-']二噻吩-4,8-二酮，一种具有高度对称平面和共轭结构且无α-H优势的醌分子，表现出高氧化还原电位、扩散系数和电化学稳定性，因此具有最佳的ORR活性和抑制副产物生成的能力。这表明溶液介导的ORR途径的增加在抑制放电副反应中起重要作用，显著提高了电池的循环稳定性和容量。本研究为更好地理解Li-O电池的ORR过程提供了理论和实验依据。
