Continuous and integrated PEDOT@Bacterial cellulose/CNT hybrid helical fiber with “reinforced cement-sand” structure for self-stretchable solid supercapacitor

Abstract As the demand for wearable electronic devices persistent to booming, the stretchability of supercapacitors is essential. However, it is still challenging in preparing fiber-based stretchable supercapacitors with the self-stretchable structure instead of relying on an elastic matrix. Here, we constructed a self-stretchable poly(3,4-ethylenedioxythiophene)(PEDOT)@bacterial cellulose(BC)/Carbon nanotube (CNT) hybrid helical fiber with “reinforced cement-sand” structure through wet-spinning and coiling processes by using dissolved BC as bonded matrix, undissolved BC nanofibers and CNT as supporters, PEDOT as reinforcements materials. This structure avoids the disadvantage of relying on the elastic matrix or auxiliary materials to provide elasticity. More importantly, the helical fiber can exhibit the ultimate stretch of 1175%, and the cyclic tests demonstrate the remarkable cycle stability after 100 times of 100% cyclic stretching. Meanwhile, the self-stretchable PEDOT@BC1/CNT2 hybrid helical fiber electrodes show a gravimetric specific capacitance as high as 175.1F/g, which can remain stable under different bending degrees and tensile strains. The energy density and power density of the solid supercapacitor can reach 4.0 Wh/kg and 120.1 W/kg, respectively. This work provides a new strategy of stretchable supercapacitors independent of elastic materials, which will show wide application prospects in wearable electronic products.