Constructing a Hierarchical Ternary Hybrid of PEDOT:PSS/rGO/MoS2 as an Efficient Electrode for a Flexible Fiber-Shaped Supercapacitor

Improving the specific capacitance and energy density of a fiber-shaped supercapacitor (FSSC) is critical to its applications as an energy storage device for advanced smart wearable electronics. In this paper, a heterogeneous poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/reduced graphene oxide/molybdenum disulfide (PEDOT:PSS/rGO/MoS2) fiber was prepared to achieve a high-performance and durable electrode for the FSSC. As indicated, pseudocapacitive MoS2 was in situ grown on a highly conductive acid-treated PEDOT:PSS/rGO assembly with a hierarchical structure. This structural design emphasizes the wrinkled morphology and high conductivity of the PEDOT:PSS/rGO backbone to maximize the MoS2 deposition and accelerate its electron transfer, which fully utilizes the pseudocapacitance of MoS2 and provides additional capacitance contribution to the obtained device. Attributed to the synergy, the prepared fiber electrode in the FSSC exhibits high volumetric/areal specific capacitance (325.8 F cm–3/405.3 mF cm–2 at 1 A cm–3 or 1.2 mA cm–2) and excellent rate performance (82%, 1–10 A cm–3). The corresponding device shows an ultrahigh volumetric energy density of 6.9 mW h cm–3 at a high power density of 173.6 mW cm–3 and an areal energy density of 8.5 μW h cm–2 at 215.9 μW cm–2, together with excellent cycle stability and mechanical flexibility, outperforming most of the previously reported FSSCs. Accordingly, the proposed strategy provides a great opportunity to develop a high-performance FSSC for further wearable electronics.