Amphiphilic silane-MXene hybrids for high-performance flexible symmetric supercapacitors via additive-free processing

Abstract

Flexible and wearable microsupercapacitors demand MXene electrodes with strong substrate adhesion, high conductivity, and long-term mechanical durability—yet conventional MXene inks, relying on polymeric binders, suffer from conductivity loss and delamination due to weak interfacial interactions. A next-generation MXene (Ti₃C₂T_x) ink is developed, offering a transformative approach to flexible and wearable microsupercapacitors. Conventional MXene inks rely on polymeric binders to adhere to plastic substrates, but these binders typically degrade electrical conductivity and cause delamination due to weak interfacial interactions. Herein, a new class of MXene ink is formulated using a multifunctional alkoxysilane-based amphiphilic oligomer (AFAO) that acts simultaneously as a dispersant, an adhesion promoter, and a binder. This design enables MXene to be stably dispersed in organic solvents, strong adhesion to PET substrates, and retention of the intrinsic capacitance without any conductive additives. Electrodes prepared from this ink achieve 92.0% capacitance retention (211.2 F g⁻¹ at 1 A g⁻¹ in 1 M H₂SO₄) and maintain 100% performance after 1500 cycles under 180° bending. This multifunctional-ink strategy represents a significant paradigm shift in MXene processing, overcoming long-standing limitations in adhesion, dispersion stability, and electrochemical performance for flexible supercapacitor applications.