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Millimeter-sized few-layer graphene sheets with aligned channels for fast lithium-ion charging kinetics
Journal of Energy Chemistry ( IF 14.0 ) Pub Date : 2020-06-25 , DOI: 10.1016/j.jechem.2020.05.069
Yu-Qi Zhou , Xiao-Ling Dong , Wen-Cui Li , Guang-Ping Hao , Dong Yan , An-Hui Lu

Assembly of the top-down graphene units mostly results in 3D porous structure with randomly organized pores. The direct bottom-up synthesis of macroscopic 2D graphene sheets with organized pores are long sought in materials chemistry field, but rarely achieved. Herein, we present a self-catalysis-assisted bottom-up route using L-glutamic acid and iron chloride as starting materials for the fabrication of the millimeter-sized few-layer graphene sheets with aligned porous channels parallel to the 2D direction. The amino- and carboxyl-functional groups in L-glutamic acid can coordinate with iron cations, thus allowing an atomic dispersion of iron cations. The pyrolysis thus initiated the growth of graphene catalyzed by in-situ generated iron nanoparticles, and a dynamic flow of iron nanoparticles eventually led to the formation of millimeter-sized few-layer graphene sheets with aligned channels (60–85 nm in diameter). Used as anodes in lithium-ion batteries, these graphene sheets showed a good rate capability (142 mA h g−1 at 2 A g−1) and high capacity retention of 93% at 2 A g−1 after 1200 cycles. Kinetic analysis revealed that lithium ions storage was dominated by diffusion behavior and capacitive behavior together, in that graphene sheets with aligned channels could accelerate electron transfer and shorten lithium ions transport pathway. This work provides a novel approach to prepare unique porous graphene materials with specific structure for energy storage.



中文翻译:

毫米大小的几层石墨烯片,具有对齐的通道,可实现快速的锂离子充电动力学

自顶向下的石墨烯单元的组装主要产生具有随机组织的孔的3D多孔结构。在材料化学领域中,人们一直在寻求具有组织孔的宏观二维石墨烯片的直接自下而上的合成,但是很少能实现。在这里,我们提出了一种自催化辅助的自下而上的路线,该路线以L-谷氨酸和氯化铁为原料,用于制造具有平行于2D方向的对齐多孔通道的毫米大小的几层石墨烯片。L-谷氨酸中的氨基和羧基官能团可与铁阳离子配位,从而使铁阳离子原子分散。因此,热解引发了石墨烯的原位催化生长。生成的铁纳米颗粒,铁纳米颗粒的动态流动最终导致形成具有对齐通道(直径60-85 nm)的毫米大小的几层石墨烯片。用作锂离子电池的阳极,这些石墨烯片显示出良好的倍率性能(142毫安ħ克-1以2A克-1),并在2甲克的93%的高容量保持-1 1200次循环之后。动力学分析表明,锂离子的储存主要由扩散行为和电容行为共同控制,因为具有对齐通道的石墨烯片可以加速电子转移并缩短锂离子的传输路径。这项工作提供了一种新颖的方法来制备具有特定结构以存储能量的独特多孔石墨烯材料。

更新日期:2020-06-25
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