Influence of Carbon Matrix Dimensions on the Electrochemical Performance of Germanium Oxide in Lithium‐Ion Batteries
Influence of Carbon Matrix Dimensions on the Electrochemical Performance of Germanium Oxide in Lithium‐Ion Batteries
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DOI：
10.1002/ppsc.201500137
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发表时间：
2016-08
影响因子：
2.7
通讯作者：
Xiang Wei;Weihan Li;L. Zeng;Yan Yu
中科院分区：
文献类型：
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作者：
Xiang Wei;Weihan Li;L. Zeng;Yan Yu
二氧化锗（GeO2）最近被证明具有很高的理论容量，被认为是最有希望替代锂离子电池商用碳基阳极的候选者。然而，循环过程中体积的巨大变化极大地阻碍了GeO2材料在锂离子电池中的实际应用。本文采用简单的方法制备了不同碳基质（即0D介孔碳微球、1D碳纳米管、2D还原氧化石墨烯）中的GeO2分散体。在这三种复合材料的比较中，嵌入在0D介孔碳微球（表示为GeO2@MCS）中的GeO2在循环性能（100次循环后以0.5 a g−1的速率为852 mA h g−1）和速率能力（50次循环后以10 a g−1的速率为269 mA h g−1）方面表现出最佳的电化学性能。电化学性能的提高源于新型结构，它结合了多种优点：电解质易于获取和Li+的短输运路径，以及电子通过MCS矩阵的三维互联通道的高导电性输运。此外，MCS的三维互联孔隙可以有效地容纳循环过程中GeO2的巨大体积变化，并在整个电极上保持良好的导电性。
Germanium dioxide (GeO2) has recently demonstrated high theoretical capacity and is being considered as the most promising candidate to substitute commercial carbon‐based anodes of lithium‐ion batteries. Nevertheless, practical application of GeO2 materials to lithium‐ion batteries is greatly hampered by the huge volume variation during cycling. Herein, the GeO2 dispersions in different carbon matrices (i.e., 0D mesoporous carbon microspheres, 1D carbon nanotube, 2D reduced graphene oxide) are prepared by a simple route. In a comparison of these three composites, GeO2 embedded in 0D mesoporous carbon microspheres (denoted as GeO2@MCS) shows the best electrochemical performance regarding cyclability (852 mA h g−1 at a rate of 0.5 A g−1 after 100 cycles) and rate capability (269 mA h g−1 at 10 A g−1 after 50 cycles). The improved electrochemical performance arises from the novel structure that combines a variety of advantages: easy access of electrolyte and short transport path of Li+ , and high conductivity transport of electrons through the 3D interconnected channels of MCS matrix. What is more, the 3D interconnected pores of MCS could effectively accommodate the huge volume change of GeO2 during cycling and maintain perfect electrical conductivity throughout the electrode.