Improved electrochemical performance of LiMn2O4 surface-modified by a Mn4+-rich phase for rechargeable lithium-ion batteries
Improved electrochemical performance of LiMn2O4 surface-modified by a Mn4+-rich phase for rechargeable lithium-ion batteries
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DOI：
10.1016/j.electacta.2016.05.075
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发表时间：
2016-08
影响因子：
6.6
通讯作者：
Cheng-Gong Han;Chunyu Zhu;G. Saito;T. Akiyama
中科院分区：
文献类型：
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作者：
Cheng-Gong Han;Chunyu Zhu;G. Saito;T. Akiyama
通过简单的溶胶-凝胶方法制备的不同数量的富 Mn4+ 相对尖晶石 LiMn2O4 的表面进行改性，以改善高温下的电化学性能。 X 射线衍射 (XRD) 和扫描电子显微镜 (SEM) 分别证明了 LiMn2O4 颗粒无杂质且均匀的形貌。 LiMn2O4表面修饰的富Mn4+相减轻了电解液中锰的溶解，从而相对于裸LiMn2O4提高了循环性能和倍率性能。 1 wt.% 改性的 LiMn2O4 在 1C 和 25 °C 下循环 200 次后，容量保持率为 92.7%，放电容量为 113.5 mAh g−1，而裸 LiMn2O4 的容量保持率为 83.1%，放电容量为 100.8 mAh g−1。此外，经过 100 次循环后，1 wt.% 改性的 LiMn2O4 在 55 °C 下的容量保持率为 88.6%，高于裸 LiMn2O4 的 76.0%。此外，该样品显示了所有样品中最好的速率能力。富Mn4+相是修饰表面以抑制锰溶解的合适候选物，从而改善LiMn2O4的电化学性能。
The surface of spinel LiMn2O4is 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 LiMn2O4particles are demonstrated from the X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The Mn4+-rich phase modified on the surface of the LiMn2O4alleviates the dissolution of manganese in the electrolyte, thus improving the cycling performance and rate capability relative to the bare LiMn2O4. 1 wt.%-modified LiMn2O4delivers a capacity retention of 92.7% and a discharge capacity of 113.5 mAh g−1after 200 cycles at 1C and 25 °C, compared with that of 83.1%, and 100.8 mAh g−1for the bare LiMn2O4. In addition, after 100 cycles, a capacity retention of 88.6% at 1C is achieved for 1 wt.%-modified LiMn2O4at 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.