Preliminary investigation of electrical conductivity of monolithic biochar
Preliminary investigation of electrical conductivity of monolithic biochar
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DOI：
10.1016/j.carbon.2017.01.069
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发表时间：
2017-05-01
期刊：
影响因子：
10.9
通讯作者：
Jia, Charles Q.
中科院分区：
文献类型：
--
作者：
Gabhi, Randeep S.;Kirk, Donald W.;Jia, Charles Q.
整体式生物炭被探索作为超级电容器的电极材料，超级电容器是一种快速充电、持久的储能装置。电极的导电性对于超级电容器的性能至关重要。传统上，生物炭被用作燃烧的固体燃料，其中电导率在很大程度上是不相关和被忽略的。这项工作探索了整体生物炭的导电性，并阐明了其对生物炭微观和宏观结构的依赖性。发现生物炭的电导率高度依赖于其碳化程度。当生物炭的碳含量从 86.8 wt% 变化到 93.7 wt% 时，其体积电导率可增加六个数量级以上。透射电子显微镜和 X 射线衍射分析表明，在 950 摄氏度热处理后，存在石墨纳米晶体（类似于 3 nm）以及生物炭结晶度的增长。在含 96.2 wt% 碳的热处理糖枫生物炭中发现，碳的最高骨架电导率为 343.2 S/m。垂直于石墨烯平面方向高于石墨单晶（3333S/m）。此外，观察到整体生物炭的电导率随着压缩载荷的增加而增加，并在载荷释放时下降到压缩前的水平——这种新现象被称为“生物炭电导率的弹性行为”。 (C) 2017 Elsevier Ltd. 保留所有权利。
Monolithic biochar is explored as electrode material in supercapacitor - a fast-charging, long-lasting energy storage device. Electrical conductivity of electrode is critical to supercapacitor's performance. Traditionally, biochar is used as a solid fuel for combustion where electrical conductivity is largely irrelevant and ignored. This work explores electrical conductivity of monolithic biochar and elucidates its dependence on micro and macro structures of biochar. Electrical conductivity of biochar was found to be highly dependent on its degree of carbonization. Bulk conductivity of biochar can increase by over six orders of magnitudes when its carbon content changes from 86.8 to 93.7 wt%. Transmission electronic microscope and x-ray diffraction analyses revealed the presence of graphite nanocrystals (similar to 3 nm) and the growth of biochar crystallinity after heat treatment at 950 degrees C. The highest skeletal conductivity of carbon was 343.2 S/m, found in a heat-treated sugar maple biochar with 96.2 wt% of carbon. It is higher than that of graphite single crystal in direction perpendicular to graphene plane (3333 S/m). Moreover, it was observed conductivity of monolithic biochar increased with compressive loading and dropped to the pre-compression level when the loading was released - a new phenomenon termed "elastic behavior of electrical conductivity of biochar". (C) 2017 Elsevier Ltd. All rights reserved.