J. Mater. Chem. A, 2015,3, 13933-13945
Mitigating capacity fade by constructing highly ordered mesoporous Al2O3/polyacene double-shelled architecture in Li-rich cathode materials
Ming Xu,aZhaoyong Chen,Huali Zhu,aXiaoyan Yan,aLingjun Lia and Qunfang Zhaoa
* Corresponding authors
aSchool of Physics and Elctronic Science, Changsha University of Science and Technology, Changsha, China
Lithium-rich layered oxides,xLi2MnO3·(1 −x)LiMO2(M = Ni, Mn, Co), have been considered as one of the most promising cathode active materials for rechargeable lithium-ion batteries due to their high capacity over 250 mA h g−1between 2.0 and 4.8 V. However, the commercialized application of these cathodes has so far been hindered by their severe capacity fading and transition metal dissolution during high voltage cycling (>4.5 Vvs.Li/Li+). To overcome this barrier, a double-shelled architecture consisting of an inner conductive polyacene layer and an outer mesoporous Al2O3layer is constructed. A polyacene layer with high electron conductivity is first coated on the surface of a 0.5Li2MnO3·0.5LiNi0.5Co0.2Mn0.3O2cathode material, followed by a hydrothermal method combined with an in-sol treatment to produce a highly ordered mesoporous Al2O3layer. Compared to previous studies, this double-shelled architecture has substantially improved the electrochemical performance of the 0.5Li2MnO3·0.5LiNi0.5Co0.2Mn0.3O2cathode material. Two striking characteristics are obtained for this double-shelled lithium-rich layered oxide cathode material: (1) the electrochemical capacity is greatly improved, reaching 280 mA h g−1(2.0 V–4.8 V at 0.1 C) and (2) the transition from the layered phase to spinel is delayed, leading to a superior capacity retention of 98% after the 100thcycle.