Ti3C2Tx MXene coated carbon fibre electrodes for high performance structural supercapacitors

Abstract

MXenes, while excellent for electrical energy storage, face challenges in translating their nanoscale properties to macroscale structures. To address this, MXene-coated carbon fibers (CF) were developed as electrode materials for structural supercapacitor composites. CF surface chemistry was tailored using aryl diazonium salts (–NO2, –NH2, -SH, –COOH) to optimize MXene adhesion. Electrodes were characterized for surface chemistry, morphology, and properties including electrochemical, mechanical, and interfacial aspects. Electrodes developed from MXene coated on CF functionalized with a poly(o-phenyelenediamine) coating exhibited a specific capacitance of 157 F/g−1 at 5 mV s−1, a ∼725-fold improvement in capacitance compared to pristine unfunctionalized CF, with minimal to no compromise in the underlying strength and stiffness of the CF. The MXene coating also improved the interfacial adhesion of the electrode to an epoxy-based resin by 54 %. The process was scaled up to functionalize and coat woven CF mats and were used to fabricate a structural supercapacitor device. The device exhibited a specific capacitance of 908 mF/g−1 at 0.5 mA g−1, representing a remarkable ∼42-fold improvement compared to the control. This lightweight multifunctional supercapacitor composite holds great potential in aerospace, automotive, and renewable energy storage sectors, addressing global challenges tied to fossil fuel combustion and associated environmental and socio-economic issues.