Engineering binder-free carbonaceous-metal oxide composite electrodes for next-generation flexible asymmetric supercapacitors

Carbonaceous materials and metals oxide are successfully prepared in large scale as a composite electrode by applying a synthesis DC sputtering method. The synergistic contribution of each component is utilized in this approach. The binder-free architecture promotes efficient charge transport and strong interfacial contact. Composite thin-film electrodes comprising C-V₂O₅ (positive) and C-SnO₂ (negative) were deposited onto a conductive tantalum substrate by reactive DC magnetron co-sputtering. These electrodes show good structural stability, thus superior electrochemical performances are obtained for the asymmetrical supercapacitor C-V 2 O 5 //C-SnO 2 , which operates at + 1.8 V and delivers an areal capacitance of 6.8 mF cm −2 at 0.1 mA cm −2 . The as-fabricated device presents a high energy density of 20.02 Wh/kg at a power density of 655.36 W/kg and retains 88.6% of its original capacitance in flat devices and 80.30% in flexible devices upon completion of 10,000 cycles. The flexibility of the composite electrodes further enables the design of highly flexible ACS devices that can be integrated with a wide range of wearable and portable electronics. These excellent electrochemical performances endow the assembled asymmetric supercapacitor as desirable power sources for various devices such as energy harvesting, energy storage and flexible electronics. These results demonstrate the potential of the developed electrodes for flexible and wearable energy-storage application.