An In Situ Formed Surface Coating Layer Enabling LiCoO2 with Stable 4.6 V High‐Voltage Cycle Performances. Issue 28 (15th June 2020)

• Record Type: Journal Article
• Authors: Wang, Yi; Zhang, Qinghua; Xue, Zhi‐Chen; Yang, Lufeng; Wang, Junyang; Meng, Fanqi; Li, Qinghao; Pan, Hongyi; Zhang, Jie‐Nan; Jiang, Zheng; Yang, Wanli; Yu, Xiqian; Gu, Lin; Li, Hong
• Is Part Of: Advanced energy materials. Volume 10:Issue 28(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-06-15
• Subjects: cathodes -- lithium cobalt oxide -- lithium‐ion batteries -- solid electrolytes -- surface coating; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.202001413
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: The development of high‐voltage LiCoO2 is essential for achieving lithium‐ion batteries with high volumetric energy density, however, it faces a great deal of challenges owing to the materials, structure and interfacial instability issues. In this work, a strategy is developed, through heat annealing a precoated surface layer to in situ form a high‐voltage‐stable surface coating layer, which is demonstrated to be highly effective to improve the high‐voltage performance of LiCoO2 . It is discovered that LiCoO2 reacts with Li1.5 Al0.5 Ti1.5 (PO4 )3 (LATP) at 700 °C to form exclusively spinel phases in addition to Li3 PO4, which are structurally coherent to the layered lattice of LiCoO2 . The heat annealing of the precoated thin layer of LATP enables the formation of a high‐quality surface layer. Spinel phases possess high‐voltage‐stable structures with much weaker oxidizing ability of lattice oxygen than layered structure. In addition, the Li3 PO4 is a good lithium‐ion conductor with excellent chemical stability at high voltages. All these benefits contribute to the construction of a uniform and conformal high‐voltage‐stable surface layer with favorable lithium conducting kinetics at the LiCoO2 surface. The modified LiCoO2 shows excellent 4.6 V high‐voltage cycle performance at both room temperature and 45 °C. The thermal stability is greatly enhanced as well. Abstract : In situ construction of a high‐voltage‐stable surface coating layer on the LiCoO2 surface is achieved by heat annealing the precoated Li1.5 Al0.5 Ti1.5 (PO4 )3 surface layer. The surface‐modified LiCoO2 shows superior 4.6 V high‐voltage cycle performances at both room temperature and 45 °C. The thermal stability of the modified sample is enhanced as well.