Electrochemically Inert Li2MnO3: The Key to Improving the Cycling Stability of Li-Rich Manganese Oxide Used in Lithium-Ion Batteries |
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Authors: | Lian-Bang Wang He-Shan Hu Wei Lin Qing-Hong Xu Jia-Dong Gong Wen-Kui Chai Chao-Qi Shen |
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Institution: | State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China; (L.-B.W.); (H.-S.H.); (W.L.); (Q.-H.X.); (J.-D.G.); (W.-K.C.) |
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Abstract: | 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. |
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Keywords: | lithium-rich manganese oxide nanocomposite dynamic hydrothermal inert Li2MnO3 cycling stability |
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