Flexible supercapacitors (SCs) always face the charging issue when they are used in some special situations (e.g., wilderness island) that cannot provide electricity, which would limit the continuous energy supply for the attached wearable electronics. Herein, a self-chargeable flexible solid-state supercapacitor (FSSSC) was creatively constructed by sandwiching a piezoelectric polyvinyl alcohol/potassium hydroxide/barium titanate electrolyte between symmetric NiCo2O4@activated carbon cloth electrodes. By virtue of the efficient synergy of each component in the FSSSC, the device exhibits integrated merits with excellent flexibility, satisfactory electrochemical properties, and considerable self-charging capability through synchronously collecting and converting mechanical energy (e.g., repeated bending) into storable electrochemical energy in a persistent way. When the devices are serially connected and self-charged, they can be used to drive typical electronics with normal working. Such a unique material and device design enables the FSSSC with combined capabilities such as energy-harvesting and conversion and storage device for self-powered wearable electronics.
Keywords: flexible; piezoelectrolyte; self-chargeable; solid-state; supercapacitor.