壳聚糖制备多孔炭及其在电化学超级电容器中的应用(英文)

以壳聚糖为原料在 600、700、800和900℃直接炭化制备多孔炭 C-600,C-700, C-800 和C-900,其BET比表面积分别为278、461、515和625 m2·g-1.用恒流充放电和循环伏安法表征了其电化学性能. 结果表明, 由 C-800 制备电极的循环伏安图形更接近矩形, 在恒电流充放电实验中阴极和阳极过程基本对称, 说明该电极具有较好的电容性能.在 50 mA·g-1 的电流密度下,C-600、C-700、C-800和C-900的电容分别为96、120、154 和 28 F·g-1.由 C-800 制备电极的循环充放电稳定性好, 电流密度为1 A·g-1循环1000次后电容损失小于2%,说明壳聚糖制备多孔碳具有作为超级电容器电极材料的潜在价值. 同时还考察了不同浓度的电解液对C-800电化学性质的影响,发现在KOH浓度为 30%时的电容最大.依据实验结果,对多孔炭制备及其电化学性质间的关系进行了探讨.

Preparation of Chitosan-Based Porous Carbons and Their Application as Electrode Materials for Supercapacitors

Four porous carbon samples C-600, C-700, C-800, and C-900 were prepared by the carbonization of chitosan at 600, 700, 800, and 900 ℃ under N2 and had specific surface areas of 278, 461, 515, and 625 m2·g-1, respectively, based on nitrogen adsorption/desorption measurements. Their electrochemical properties were investigated by cyclic voltammetry (CV) and charge-discharge under constant current. The CV curves of C-800 have a rectangular shape and symmetrical anode and cathode processes. The capacitance of C-600, C-700, C-800, and C-900 are 96, 120, 154, and 28 F·g-1 derived fromthe galvanostatic charge-discharge curves at a current density of 50 mA·g-1, respectively. The C-800 composite electrode is highly stable and retains its capacitance well as the capacitance decreased by less than 2% after 1000 cycles at a current density of 1 A·g-1. Furthermore, with an increase in the concentration of the electrolyte, the shape of the CV curves of the C-800 based electrode becomes more and more rectangular and the specific current also increases. The relationship between the pore structures of the four porous carbon samples and their properties is discussed based on the experimental results. We suggest that chitosan-based porous carbon has potential application as electrochemical capacitor electrode materials.