标题：Modified structural characteristics and enhanced electrochemical properties of oxygen-deficient Li2MnO3-Δobtained from pristine Li2MnO3
作者：Tan, Xiao ;Liu, Rui ;Xie, Congxin ;Shen, Qiang
作者机构：[Tan, Xiao ;Liu, Rui ;Xie, Congxin ;Shen, Qiang ] Key Laboratory for Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Ch 更多
来源：Journal of Power Sources
摘要：Lithium-rich manganese(IV) oxide Li2MnO3has hardly any activity as the cathode active substance of lithium-ion batteries (LIBs) but its reversible capacity can be greatly improved by introducing oxygen deficiencies. After the solid-state heat treatment of nanocrystalline Li2MnO3by sodium borohydride (NaBH4), the resulting Li2MnO3-δcrystallites comparatively acquire distinguishable appearances in color and shape and slight differences in surface composition and lattice structure. As a LIB cathode within the potential range of 2.5–4.7 V, at 20 mA g−1pristine Li2MnO3gives the specific discharge capacities of 3.3, 5.0 and 7.4 mAh·g−1in the 1st, 10th and 100th cycles, while the derivative Li2MnO3-δdelivers the relatively high values of 64.8, 103.8 and 140.2 mAh·g−1in the 1st, 10th and 120th cycles, respectively. Aside from the similar phenomenon of gradual electrochemical activation, substituting Li2MnO3-δfor Li2MnO3means the great enhancements of charge-transfer ability and electrochemical performances. Especially, the cationic-anionic redox mechanisms of Li2MnO3and Li2MnO3-δare similar to each other, suggesting a possible solution to prepare high-performance xLi2MnO3-δ·(1-x)LiMO2solid solutions for application purposes.
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