Mitigating capacity fade by constructing highly ordered mesoporous Al sub(2)O sub(3)/polyacene double-shelled architecture in Li-rich cathode materials

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2015-06, Vol.3 (26), p.13933-13945
• Main Authors: Xu, Ming, Chen, Zhaoyong, Zhu, Huali, Yan, Xiaoyan, Li, Lingjun, Zhao, Qunfang
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Architecture; Cathodes; Cathodic dissolution; Fading; High voltages; Rechargeable batteries; Sustainability
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c5ta03676c

Lithium-rich layered oxides, xLi sub(2)MnO sub(3).(1 - x)LiMO sub(2) (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 super(-1) between 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 V vs. Li/Li super(+)). To overcome this barrier, a double-shelled architecture consisting of an inner conductive polyacene layer and an outer mesoporous Al sub(2)O sub(3) layer is constructed. A polyacene layer with high electron conductivity is first coated on the surface of a 0.5Li sub(2)MnO sub(3).0.5 LiNi sub(0.5)Co sub(0.2)Mn sub(0.3)O sub(2) cathode material, followed by a hydrothermal method combined with an in-sol treatment to produce a highly ordered mesoporous Al sub(2)O sub(3) layer. Compared to previous studies, this double-shelled architecture has substantially improved the electrochemical performance of the 0.5Li sub(2)MnO sub(3).0.5 LiNi sub(0.5)Co sub(0.2)Mn sub(0.3)O sub(2) cathode 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 super(-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 100 super(th) cycle.