Electroactive 1T-MoS₂ Fluoroelastomer Ink for Intrinsically Stretchable Solid-State In-Plane Supercapacitors

Full advantage of stretchable electronic devices can be taken when utilizing an intrinsically stretchable power source. High-performance stretchable supercapacitors with a simple structure and solid-state operation are good power sources for stretchable electronics. This study suggests a new type of intrinsically stretchable, printable, electroactive ink consisting of 1T-MoS₂ and a fluoroelastomer (FE). The active material (1T-MoS₂/FE) is made by fluorinating the metallic-phase MoS₂ (1T-MoS₂) nanosheets with the FE under high-power ultrasonication. The MoS₂ in the 1T-MoS₂/FE has unconventional crystal structures in which the stable cubic (1T) and distorted 2H structures were mixed. The printed line of the 1T-MoS₂/FE on the porous stretchable Au collector electrodes is intrinsically stretchable at more than ε = 50% and has good specific capacitance (28 mF cm^-2 at 0.2 mA cm^-2) and energy density (3.15 mWh cm^-3). The in-plane all-solid-state stretchable supercapacitor is stretchable at ε = 40% and retains its relative capacity (C/C_o) by 80%. This printable device platform potentially opens up the in-plane fabrication of stretchable micro-supercapacitor devices for wearable electronic applications.