Enhanced energy density of flexible asymmetric solid state supercapacitor device fabricated with amorphous thin film electrode materials

Supercapacitors have recently received immense interest in scientific community, as a complementary technology to batteries, to meet the various requirements for energy usage in practice. Amorphous MnO2 and CuS thin films are prepared on stainless steel-304 (SS) substrate by chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR) methods, respectively. Asymmetric flexible solid state supercapacitor fabricated with configuration of SS/A-MnO2/Polyvinyl acetate (PVA)-Na2SO4/A-CuS/SS delivered an impressive specific energy of 57.4 Wh kg(-1) at specific power 317 W kg(-1) and excellent cycling stability over 10,000 cycles with capacitive retention of 84%. Moreover, series configuration of two asymmetric devices shows the capability of powering 211 red LEDs for similar to 150 s after charging for 30 s.