材料科学
球磨机
化学工程
机械化学
多孔性
氧气
表面改性
碳纤维
纳米技术
复合材料
化学
有机化学
复合数
工程类
作者
Renlu Yuan,Yue Dong,Ruoyang Hou,Lei Shang,Jiapeng Zhang,Su Zhang,Xiaohong Chen,Huaihe Song
标识
DOI:10.1016/j.cej.2022.140418
摘要
Mechanical ball-milling is a commonly used method to shattering crystals or introducing defects in carbon materials. But herein, we observe that the highly porous and disordered carbon lattice of activated carbon is converted to graphitic structure during ball-milling, along with the introduction of oxygen in the bulk phase. The well-developed pores are gradually eliminated, leading to obviously decreased surface area from 1364 to 156 m2 g-1 and improved compaction density from 0.573 to 1.423 g cm-3. Due to the continuous particle cleavage, re-assembly, and cold-welding, the as-formed carbon blocks show 2 times larger in size and 4 times higher bulk oxygen content. This simultaneous crystallinity enhancement and oxygen functionalization is barely observed in other methods. The mechanism is that highly reactive carbon radicals generated by mechanical cleavage of carbon skeleton enable atom rearrangement to form large graphitic domains or being terminated by oxygenated groups. Interestingly, the capacitive energy storage performance of the ball-milled activated carbon is changed from electric-double-layer to pseudo-capacitance in aqueous electrolyte, showing significantly improved volumetric capacitances and high-rate performance. Our work provides a theoretical guidance for mechanochemistry of porous and disordered carbon materials.
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