Liu Zhaomeng, Wang Jue, Jia Xinxin, Li Wenlong, Zhang Qingfeng, Fan Ling, Ding Hongbo, Yang Hongguan, Yu Xinzhi, Li Xuanke, Lu Bingan
School of Physics and Electronics , Hunan University , Changsha 410082 , China.
College of Materials Science and Engineering , Hunan University , Yuelu, Changsha , Hunan 410082 , China.
ACS Nano. 2019 Sep 24;13(9):10631-10642. doi: 10.1021/acsnano.9b04893. Epub 2019 Sep 10.
Graphene is of great significance in energy storage devices. However, a graphene-based electrode is difficult to use in direct applications due to the large surface area and flexibility, which leads to the excessive consumption of electrolyte, low Coulombic efficiency, and electrode shedding behaviors. Herein, a special crystal carbon@graphene microsphere (CCGM) composite was successfully synthesized. The scalable carbonaceous microsphere composite displays a small specific surface area and a superior structure stability. As a potassium ion battery electrode in a half-cell, CCGM delivers an initial capacity of 297.89 mAh g with a high Coulombic efficiency of about 99%. It achieves an excellent cyclic stability with no capacity loss after 1250 cycles at the low current density of 100 mA g with a long performing period of more than one year. As the cathode for an aluminum battery, a reversible specific capacity of 99.1 mAh g at 1000 mA g is obtained. CCGM delivers a long cycle performance of about 10 000 cycles at 4000 mA g with a capacity retention of nearly 100%. Our design provides a fresh thought for the improvement of graphene-based materials, and it will greatly facilitate the application of graphene in the field of energy storage.
石墨烯在储能设备中具有重要意义。然而，基于石墨烯的电极由于其大表面积和柔韧性，难以直接应用，这会导致电解质过度消耗、库仑效率低以及电极脱落行为。在此，成功合成了一种特殊的晶体碳@石墨烯微球（CCGM）复合材料。这种可扩展的含碳微球复合材料具有小比表面积和优异的结构稳定性。作为半电池中的钾离子电池电极，CCGM的初始容量为297.89 mAh g，库仑效率约为99%，表现优异。在100 mA g的低电流密度下经过1250次循环后，它实现了出色的循环稳定性，且无容量损失，性能持续时间超过一年。作为铝电池的阴极，在1000 mA g时可获得99.1 mAh g的可逆比容量。CCGM在4000 mA g时具有约10000次循环的长循环性能，容量保持率接近100%。我们的设计为改进基于石墨烯的材料提供了新思路，将极大地促进石墨烯在储能领域的应用。
