Zhang Peng, Sun Dongfei, He Mu, Lang Junwei, Xu Shan, Yan Xingbin
Laboratory of Clean Energy Chemistry and Materials, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (P.R. China).
University of Chinese Academy of Sciences, Beijing 100049 (P.R. China).
ChemSusChem. 2015 Jun 8;8(11):1972-9. doi: 10.1002/cssc.201500306. Epub 2015 May 5.
Lithium-oxygen (Li-O2 ) batteries are receiving intense interest because of their high energy density. A new tubular δ-MnO2 material prepared by a simple hydrothermal synthesis is an efficient electrocatalyst for Li-O2 batteries. The synthesized δ-MnO2 exhibits a unique tubular structure, in which the porous walls are composed of highly dispersed ultrathin δ-MnO2 nanosheets. Such a unique structure and its intrinsic catalytic activity provide the right electrocatalyst characteristics for high-performance Li-O2 batteries. As a consequence, suppressed overpotentials-especially the oxygen evolution reaction overpotential-superior rate capability, and desirable cycle life are achieved with these submicron δ-MnO2 tubes as the electrocatalyst. Remarkably, the discharge product Li2 O2 of the Li-O2 battery exhibits a uniform nanosheet-like morphology, which indicates the critical role of the δ-MnO2 in the electrochemical process, and a mechanism is proposed to analyze the catalysis of δ-MnO2 .
锂氧（Li-O₂）电池因其高能量密度而备受关注。通过简单水热合成制备的新型管状δ-MnO₂材料是锂氧电池的高效电催化剂。合成的δ-MnO₂呈现出独特的管状结构，其多孔壁由高度分散的超薄δ-MnO₂纳米片组成。这种独特的结构及其固有催化活性为高性能锂氧电池提供了合适的电催化剂特性。因此，以这些亚微米δ-MnO₂管作为电催化剂，可实现过电位的抑制——尤其是析氧反应过电位——优异的倍率性能和理想的循环寿命。值得注意的是，锂氧电池的放电产物Li₂O₂呈现出均匀的纳米片状形态，这表明δ-MnO₂在电化学过程中的关键作用，并提出了一种机制来分析δ-MnO₂的催化作用。
