A facile prestrain-stick-release assembly of stretchable supercapacitors based on highly stretchable and sticky hydrogel electrolyte

Abstract A facile prestrain-stick-release assembly strategy for the stretchable supercapacitor device is developed based on a novel Na 2 SO 4 - a PUA/PAAM hydrogel electrolyte, saving the stretchable rubber base conventionally used. The Na 2 SO 4 - a PUA/PAAM hydrogel electrolyte exhibits high stretchability (>1000%), electrical conductivity (0.036 S cm −1 ) and stickiness. Due to the unique features of the hydrogel electrolyte, the carbon nanotube@MnO 2 film electrodes can be firmly stuck to two sides of the prestrained hydrogel electrolyte. Then, by releasing the hydrogel electrolyte, homogenous buckles are formed for the film electrodes to get a full stretchable supercapacitor device. Besides, the high stickiness of the hydrogel electrolyte ensures its strong adhesion with the film electrodes, facilitating ion and electronic transfer of the supercapacitor. As a result, excellent electrochemical performance is achieved with the specific capacitance of 478.6 mF cm −2 at 0.5 mA cm −2 (corresponding to 201.1 F g −1 ) and capacitance retention of 91.5% after 3000 charging–discharging cycles under 150% strain, which is the best for the stretchable supercapacitors.