Enhanced cycling performance of surface-doped LiMn₂O₄ modified by a Li₂CuO₂-Li₂NiO₂ solid solution for rechargeable lithium-ion batteries

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• 作者：Cheng-Gong Han ; Chunyu Zhu ; ^{chunyu6zhu@gmail.com} ; Genki Saito ; Nan Sheng ; Takahiro Nomura ; Tomohiro Akiyama ; ^{takiyama@eng.hokudai.ac.jp}
• 关键词：LiMn2O4 ; cathode ; surface modification
• 刊名：Electrochimica Acta
• 出版年：2017
• 出版时间：10 January 2017
• 年：2017
• 卷：224
• 期：Complete
• 页码：71-79
• 全文大小：4275 K
• 卷排序：224

文摘

A series of surface-doped LiMn2O4 samples modified by a Li2CuO2-Li2NiO2 solid solution were synthesized using a simple and facile sol-gel method to achieve the enhanced cycling performance, especially at elevated temperatures. The corresponding phase structure and morphology were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The modified layer on the surface of LiMn2O4 particles, featuring a LiNiδMn2–δO4-like phase, together with a Li2CuO2-Li2NiO2 solid solution, as confirmed by XRD and transmission electron microscopy (TEM), plays a key role in alleviating the dissolution of manganese, thus enhancing the cycling performance and rate capability relative to bare LiMn2O4. The 0.5 wt.%-modified LiMn2O4 sample delivers a discharge capacity of 113 mAh g−1 and a capacity retention of 93.2% following 300 cycles at 1C and 25 °C, which is higher than the values of 96 mAh g−1 and 81.2% for bare LiMn2O4. In addition, at 55 °C, a capacity retention of 81.2% at 1C is obtained for the 0.5 wt.%-modified LiMn2O4 sample after 200 cycles, compared to 70.0% for bare LiMn2O4. Modifying the surface of the latter by a LiNiδMn2–δO4-like phase mixed with a Li2CuO2-Li2NiO2 solid solution, is an effective strategy for improving electrochemical properties.