All solid-state supercapacitor with phosphotungstic acid as the proton-conducting electrolyte

For the first time, the proton-conducting composite phosphotungstic acid PTA/Al2(SO4)3·18H2O was used as the electrolyte of symmetric supercapacitor based on PANI. The optimum weight ratio of PTA/Al2(SO4)3·18H2O for using in this supercapacitor was also reported. Electrochemical tests prove that the supercapacitor using this kind of composite as electrolyte has high capacitance performance. Its capacitance is as high as 240 F/g at 6 mA. It was more important that it has long cycle life. After 1000 cycles, the attenuation of the capacitance is less than 10% and the coulombic efficiency is still greater than 96%.