Improved electrochemical performance of LiMn₂O₄ surface-modified by a Mn⁴⁺-rich phase for rechargeable lithium-ion batteries

详细信息    查看全文

• 作者：Cheng-Gong Han ; Chunyu Zhu ; Genki Saito ; Tomohiro Akiyama ; ^{takiyama@eng.hokudai.ac.jp" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Li-ion battery ; LiMn2O4 ; Mn4+-rich phase ; surface modification
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：10 August 2016
• 年：2016
• 卷：209
• 期：Complete
• 页码：225-234
• 全文大小：3551 K

文摘

The surface of spinel LiMn₂O₄ is modified with different quantities of a Mn⁴⁺-rich phase prepared by a facile sol-gel method to improve electrochemical properties at elevated temperatures. Impurity-free and uniform morphologies for the LiMn₂O₄ particles are demonstrated from the X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The Mn⁴⁺-rich phase modified on the surface of the LiMn₂O₄ alleviates the dissolution of manganese in the electrolyte, thus improving the cycling performance and rate capability relative to the bare LiMn₂O₄. 1 wt.%-modified LiMn₂O₄ delivers a capacity retention of 92.7% and a discharge capacity of 113.5 mAh g⁻¹ after 200 cycles at 1C and 25 °C, compared with that of 83.1%, and 100.8 mAh g⁻¹ for the bare LiMn₂O₄. In addition, after 100 cycles, a capacity retention of 88.6% at 1C is achieved for 1 wt.%-modified LiMn₂O₄ at 55 °C, which is higher than the 76.0% for the bare LiMn₂O₄. Furthermore, this sample shows the best rate capability among all samples. The Mn⁴⁺-rich phase is an appropriate candidate for modifying surfaces to suppress dissolution of manganese, thereby improving the electrochemical properties of LiMn₂O₄.