Syntheses and Characterizations of Supercapacitors Using Nano-Sized ZnO/Nanoporous Carbon Electrodes and PVA-Based Polymer-Hydrogel Electrolytes

摘要

Supercapacitors have been successfully fabricated using nano-sized ZnO/nanoporous carbon (nano-sized ZnO/NPC) electrodes and various hydrogel electrolytes. The nano-sized ZnO/NPC materials have been prepared from zinc acetate (Zn(CH_3COO)_2) and coconut shell using a simple heating method. Polyvinyl alcohol (PVA) hydrogel blended with phosphoric acid (H_3PO_4), lithium hydroxide (LiOH) and sodium sulfate (Na_2SO_4) electrolytes, respectively, has been located between the electrodes. Two of the nano-sized ZnO/NPC electrodes with area of 1 cm~2 and those PVA hydrogel electrolytes were pressed together and annealed at 60 °C for 60 min. to construct the supercapacitors. It has been found that the supercapacitor with nano-sized ZnO/NPC electrodes and Na_2SO_4 electrolyte has the highest capacitance of 60.4 Fg~(-1).