1.8-V flexible supercapacitors with asymmetric configuration based on manganese oxide, carbon nanotubes, and a gel electrolyte

We demonstrate the fabrication of flexible asymmetric supercapacitors with operation voltage window of 1.8 V. Carbon nanotubes and manganese-oxide-coated carbon nanotubes were used as a negative and a positive electrode material, respectively. A gel electrolyte consisting of sodium sulfate, silica nanoparticles, and poly(vinyl alcohol) was developed for the realization of flexible supercapacitors with asymmetric configuration. The supercapacitors showed high durability against mechanical bending cycles. Moreover, the supercapacitors showed decent capacitive behavior with specific capacitance of ∼56.3 F/g (at 1 A/g) and relaxation time constant of 3.16 s. Our results clearly show that the asymmetric configuration can be successfully employed for flexible solid-state supercapacitors, which may be an important foundation for the fabrication of high-performance flexible supercapacitors.