熔盐水合物处理对生物质基多孔碳材料电化学性能的影响

Effect of Molten Salt Hydrate Treatment on the Electrochemical Performance of Woody Biomass-based Porous Carbon Materials

关键词:  杨木边材木片  无机熔盐水合物  活化  多孔碳材料  电化学性能

Key Words:poplar sapwood chips  inorganic molten salt hydrate  activation  porous carbon material  electrochemical performance

摘要:本研究以速生杨木边材木片为原料进行自水解预处理，将无机熔盐水合物和自水解预处理后的杨木片（APW）加入盐酸溶液中浸渍，经冷冻干燥、碳化、酸洗、水洗及干燥后得到木质生物质基多孔碳材料。探究了APW的不同无机熔盐水合物活化处理对多孔碳材料物理结构性能的影响，测试了将其作为超级电容器电极材料的电化学性能。结果表明，在盐酸溶液中，无机熔盐水合物ZnCl₂和 ZnCO₃活化处理均有利于提高木质生物质基多孔碳材料的电化学性能，且前者比后者的作用效果更强，ZnCl₂活化处理制备的木质生物质基多孔碳材料无序结构更多；当用作超级电容器中的电极材料时，活化剂总质量一定，以ZnCl₂和ZnCO₃组合制备的多孔碳材料的电化学性能更具有优势，在0.2 A/g电流密度下，所制备的电极材料质量比容量可达到143.20 F/g；在2.0 A/g电流密度下，其循环5000次的电容保持率为99.90%；另外，在10 mV/s的扫描速率下，其循环伏安曲线保持了良好闭合的近似矩形形状。

Abstract:Fast-growing poplar sapwood chips were used as raw materials for autohydrolysis pretreatment， and both inorganic molten-salt hydrates and the autohydrolyzed poplar sapwood （APW） chips were added into the hydrochloric acid solution for immersion. The resultant APW chips were then freeze-dried， carbonized， washed respectively with dilute-acid solution and deionized water， and dried successively， and a woody biomass-based porous carbon material was finally obtained. The effect of APW chips activated with different inorganic molten-salt hydrates on the physical structure and properties of the porous carbon materials was explored， and the electrochemical performance was also tested as the porous carbon material was used as a supercapacitor electrode. The results showed that the activation treatment with inorganic molten-salt hydrate ZnCl₂ and ZnCO₃ in hydrochloric acid solution was beneficial to improving the electrochemical performance of woody biomass-based porous carbon materials， while the former was more effective than the latter. And the woody biomass-based porous carbon materials prepared by ZnCl₂ had more disordered structure. When used as a electrode material in a supercapacitor， the porous carbon material prepared with the combined activation of ZnCl₂ and ZnCO₃ was more advantageous in the electrochemical performance under a certain total-amount of the activator. At a current density of 0.2 A/g， its specific capacity reached 143.20 F/g. After 5000 cycles of charge-discharge process at the current density of 2.0 A/g， the retention of specific capacitance was as high as 99.90%， indicating that the material had fine cycle stability. In addition， at a scanning rate of 10 mV/s， its cyclic voltammetry curve maintained a well-closed and approximately rectangular shape.