Reconfigurable solid-state electrolytes for high performance flexible supercapacitor

To realize high performance and a flexible supercapacitor, it is necessary to address the fundamental issues including low ionic conductivity of solid electrolytes and high interfacial resistance of electrode/electrolyte pairs. Here we present unique solid-state electrolytes by integrating highly engineered nano-porous polyvinyl alcohol (PVA) with super-flat vertically aligned single-walled carbon nanotubes (VA-SWNTs). Highly engineered PVA nano-porous films are fabricated by a generic freeze-thaw process followed by water-miscible solvent treatment in order to create highly controlled nano/microscale pores inside of PVA. Such highly porous PVA films act as both reconfigurable electrolyte template and separator where H3PO4 aqueous solution or ionic liquids can be selectively inserted for a variety of power requirements in flexible electronic applications. Our developed pore formation process is suitable for directly integrating high performance VA-SWNTs electrode as it allows the effective permeation of the polymer electrolyte into nanoscale inter-tube space enabling the easy access and faster transport of ions for higher power capability. This unique entity of reconfigurable electrolyte and nanostructured electrode demonstrates high power and energy densities and remarkable stability after 10,000 charge/discharge cycles.