All solid supercapacitors based on an anion conducting polymer electrolyte

摘要

In this paper, KOH doped polybenzimidazole (PBI-KOH), an anion conducting polymer electrolyte, has been employed to demonstrate the possibility of fabricating alkaline all solid supercapacitors. This is different from the conventional gel-electrolyte based quasi-solid supercapacitors. Symmetric devices assembled using commercial activated carbon based electrodes and PBI-KOH electrolytes exhibit a high rate capability with specific capacitance retention above 90% when the discharge current density increased from 0.5 to 20 A g(-1). However, PBI-KOH suffers from low cycling stability with a rapid decrease in specific capacitance in the first 1000 cycles. By adding a binder or narrowing the potential window, the cycling stability could be improved. The best device shows a quite stable performance during the first 2000 cycles with specific capacitance degradation of less than 5%. An asymmetric (or hybrid) device has been assembled using activated carbon and Ni(OH)(2) as electrode materials, which exhibits a relative high specific energy of 37.1 W h kg(-1). These results strongly recommend the great potential of solid anion conducting polymer electrolytes in developing alkaline all solid supercapacitors.