Effect of ZnCl2 impregnation concentration on the microstructure and electrical performance of ramie-based activated carbon hollow fiber

Activated carbon hollow fibers (ACHFs) with high surface area were prepared from natural ramie fibers (RFs) by one-step activation under different ZnCl2 impregnation concentrations. The results showed that the morphology and pore structure development of ACHFs depend greatly on ZnCl2 concentration because ZnCl2 not only can swell and dissolve cellulose but also can serve as skeleton of newborn pores. It obtained granular activated carbons (ACs) instead of ACHFs when ZnCl2 concentration was over a suitable range. As supercapacitor electrode, the ACHFs possessed the maximum capacity of 287 F g(-1) and showed excellent stability with more than 93 % efficiency after 1000 cycles. Besides, ACHFs showed higher electrochemical performance than granular ACs even if their microstructure was similar, indicating the morphology of material is also important to the electrochemical properties. Therefore, supercapacitors using ramie-based ACHFs as electrodes possess high comprehensive properties to serve for the need of backup energy storage and high pulse power applications.