Membrane-assisted assembly strategy of flexible electrodes for multifunctional supercapacitors

Developing flexible electrode is essential for new generation wearable electronics and energy devices. Combining with membrane-assisted vacuum filtration, highly flexible and stable hybridized electrodes, containing of S-doped graphene, carbon nano-onion (OLC) and Ni3S2 composite (GCNi3S2) are obtained. X-ray absorption characterizations reveal the transfer of electrons from C to Ni atoms due to the tight interface between Ni3S2 and GO/OLC, indicating the synergistic effect on fast redox reaction and ultrashort ion diffusion pathway among the hybrid electrodes. The assembled flexible symmetrical all-solid-state supercapacitor exhibits high volumetric capacitance of 55.3 F cm−3, along with an outstanding energy density of 3.63 Wh cm−3 and excellent stability of 5000 cycles with 97.2% capacitance remaining. The bending tests further confirm outstanding flexible performance in the capacitor device. Moreover, the assembled micro supercapacitor with GCNi3S2 electrode indicates the advantage of this membrane-assisted assembled strategy for easily realizing various flexible films as multitype supercapacitor's electrode which is otherwise difficult for powder-like materials.