Here we report a solid state flexible supercapacitor based on high surface area activated carbon and electrospun nanofibers of anatase phase titanium dioxide. The granular and high aspect ratio nanofibers were synthesized by sol-gel assisted electrospinning followed by calcination. Flexible and transparent thin film prepared from polyvinyl alcohol and phosphoric acid was used as electrolyte cum separator for the supercapacitor. The flexible supercapacitor achieved high specific capacitance of 310 F/g with higher energy density and excellent rate capability. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.