fig4

Figure 4. Photographs of HPF-based FSCs of ~4 cm in length at the (A) straight and bent at (B) 90° and (C) 180° states. (D) CV curves of the FSCs bent at different angles at a scan rate of 20 mV s^-1. (E) CV curves of FSCs before and after bending at 180° for 3000 times. (F) Optical image of two individual FSCs based on HPF electrodes connected in series to light up a green LED. Fabricated textile devices integrated into the cloth with four HPFs connected in parallel to power an electronic timer at the (G) flat and (H) bending 180° states. (I) Demonstration of a flexible wearable device. HPF: Hollow poly(3,4-ethylenedioxythiophene):polystyrene sulfonate thin-walled fibers; FSC: fiber-shaped supercapacitor; CV: cyclic voltammetry.