Titanium carbide sheet based high performance wire type solid state supercapacitors

Abstract

Two dimensional sheets based on transition metal carbides have attracted much attention in electrochemical energy storage sectors. In this work, we demonstrated the fabrication and performance of titanium carbide based wire type supercapacitors (WSCs) towards next generation energy storage devices. The layered titanium carbide sheets were prepared via selective extraction of Al from the precursor Ti₂AlC using hydrofluoric acid and are extensively characterized using X-ray diffraction, field emission scanning electron microscopy, high resolution transmission electron microscopy, Fourier transform-infrared spectroscopy, and laser Raman spectral analyses, respectively. The X-ray photoelectron spectroscopy studies confirmed the presence of oxygen and fluorinated functional groups attached on the surface of titanium carbide. The electrochemical studies of the fabricated titanium carbide WSC devices showed ideal capacitive properties with a specific length capacitance of 3.09 mF cm⁻¹ (gravimetric capacitance of about 4.64 F g⁻¹), and specific energy density of about 210 nW h cm⁻¹ (in length) or 315 mW h kg⁻¹ (in gravimetric) with excellent cycling stability. Further, a detailed examination of the capacitive and charge-transfer behavior of titanium carbide WSCs has been investigated via electrochemical impedance analysis using Nyquist and Bode plots. Additionally, we have also demonstrated the practical application of the titanium carbide WSCs, highlighting the path for their huge potential in energy storage and management sectors.