High-performance flexible transparent micro-supercapacitors from nanocomposite electrodes encapsulated with solution processed MoS₂ nanosheets

Two-dimensional molybdenum disulfide (MoS₂) nanosheets have emerged as a promising material for transparent, flexible micro-supercapacitors, but their use in electrodes is hindered by their poor electrical conductivity and cycling stability because of restacking. In this paper, we report a novel electrode architecture to exploit electrochemical activity of MoS₂ nanosheets. Electrochemically exfoliated MoS₂ dispersion was spin coated on mesh-like silver networks encapsulated with a flexible conducting film exhibiting a pseudocapacitive behavior. MoS₂ nanosheets were electrochemically active over the whole electrode surface and the conductive layer provided a pathway to transport electrons between the MoS₂ and the electrolyte. As the result, the composite electrode achieved a large areal capacitance (89.44 mF cm⁻² at 6 mA cm⁻²) and high energy and power densities (12.42 µWh cm⁻² and P = 6043 µW cm⁻² at 6 mA cm⁻²) in a symmetric cell configuration with 3 M KOH solution while exhibiting a high optical transmittance of ~80%. Because the system was stable against mechanical bending and charge/discharge cycles, a flexible micro-supercapacitor that can power electronics at different bending states was realized.