Electrochemically Inert Li2MnO3: The Key to Improving the Cycling Stability of Li-Rich Manganese Oxide Used in Lithium-Ion Batteries

• Published in: Materials Vol. 14; no. 16; p. 4751
• Main Authors: Wang, Lian-Bang, Hu, He-Shan, Lin, Wei, Xu, Qing-Hong, Gong, Jia-Dong, Chai, Wen-Kui, Shen, Chao-Qi
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 23.08.2021; MDPI
• Subjects: Cathodes; Control stability; Crystal defects; Cycles; cycling stability; dynamic hydrothermal; Electrochemical analysis; Electrode materials; inert Li2MnO3; Lithium; Lithium-ion batteries; lithium-rich manganese oxide; Manganese oxides; Microscopy; nanocomposite; Nanocomposites; Nanoparticles; Rechargeable batteries; Structural stability; Work stations; United States > US; Netherlands; China
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14164751

Lithium-rich manganese oxide is a promising candidate for the next-generation cathode material of lithium-ion batteries because of its low cost and high specific capacity. Herein, a series of xLi2MnO3·(1 − x)LiMnO2 nanocomposites were designed via an ingenious one-step dynamic hydrothermal route. A high concentration of alkaline solution, intense hydrothermal conditions, and stirring were used to obtain nanoparticles with a large surface area and uniform dispersity. The experimental results demonstrate that 0.072Li2MnO3·0.928LiMnO2 nanoparticles exhibit a desirable electrochemical performance and deliver a high capacity of 196.4 mAh g−1 at 0.1 C. This capacity was maintained at 190.5 mAh g−1 with a retention rate of 97.0% by the 50th cycle, which demonstrates the excellent cycling stability. Furthermore, XRD characterization of the cycled electrode indicates that the Li2MnO3 phase of the composite is inert, even under a high potential (4.8 V), which is in contrast with most previous reports of lithium-rich materials. The inertness of Li2MnO3 is attributed to its high crystallinity and few structural defects, which make it difficult to activate. Hence, the final products demonstrate a favorable electrochemical performance with appropriate proportions of two phases in the composite, as high contents of inert Li2MnO3 lower the capacity, while a sufficient structural stability cannot be achieved with low contents. The findings indicate that controlling the composition through a dynamic hydrothermal route is an effective strategy for developing a Mn-based cathode material for lithium-ion batteries.