High-energy density nanofiber-based solid-state supercapacitors
By Lawrence, Daniel W. and Tran, Chau and Mallajoysula, Arun T. and Doorn, Stephen K. and Mohite, Aditya and Gupta, Gautam and Kalra, Vibha
Published in J. Mater. Chem. A
The Royal Society of Chemistry
2016
Abstract
We have developed binder-free solid-state electric double layer supercapacitors using freestanding porous carbon nanofiber electrodes fabricated using electrospinning and silica-based ionic liquid gel electrolytes. To ensure close electrode/electrolyte contact and efficient transport of ions for high power operation, we fabricated our electrodes by uniformly filling freestanding samples of porous carbon nanofiber mats with a blend of silica sol-gel precursor and ionic liquid electrolyte, which were then appropriately dried/gelled to form all-solid supercapacitors. Two different carbon nanofiber samples have been investigated with high specific surface areas of 1218 m2 g-1 and 2282 m2 g-1. The resulting solid-state supercapacitor can operate in a large voltage window of 3.5 V. We achieved specific capacitance (Csp) and specific energy (Ecell, based on the mass of the two electrodes) of up to 144 F g-1 and 61 W h kg-1 respectively, rivaling that of lead-acid batteries, with a high active material (carbon only) loading of 3-5 mg cm-2.