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/MoS 2 ) fiber was prepared to achieve a high-performance and durable electrode for the FSSC. As indicated, pseudocapacitive MoS 2 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 MoS 2 deposition and accelerate its electron transfer, which fully utilizes the pseudocapacitance of MoS 2 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.