Flexible all-solid-state asymmetric supercapacitor based on three-dimensional MoS2/Ketjen black nanoflower arrays

Abstract

Abstract High electrochemical properties of negative electrode materials are highly desirable for flexible asymmetric supercapacitors (ASCs). Although benefiting from the unique structure and broad operation potential, molybdenum disulfide (MoS2) has caused concern as a negative electrode material because its low electrochemical stability and poor conductivity hinder the exploitation of its application in flexible ASCs. Here we investigated a facile two-step hydrothermal approach to fabricate MoS2/Ketjen black (KB) composites on flexible carbon cloth. Following the construction of flower-like MoS2 on carbon cloth, KB nanospheres were embedded in MoS2 via a secondary hydrothermal route. The as-prepared MoS2/KB electrode presents a high capacitance of 429 F g−1 at a current specific of 1 A g1. In addition, the hybrid ASC device of NiCo2O4//MoS2/KB was built, which delivers a high energy density of 25.7 Wh kg−1 and power density of 16 kW kg−1. These results are ascribed to the favorable structure of MoS2 and inherently superior conductivity of KB, which improves wettability, structural stability and electronic conductivity. In brief, the proposed all-solid-state ASC device offers potential application in future portable electronics and flexible energy storage devices.