Exploring the Potential of Nb2CTx MXene in Ferroelectrics and Metal Ions Intercalation in Ti₃CNTₓ MXene for Efficient Energy Storage Applications

Abstract

This study presents the first comprehensive investigation of 2D Nb₂CTₓ MXene as a potential candidate for ferroelectric and memory applications. A detailed structural, morphological, and electrical analysis confirmed its inherent ferroelectric properties, providing valuable insights into its fundamental behavior and suitability for next-generation electronic and memory devices. Additionally, the Ti₃CNTₓ MXene was successfully synthesized via mild etching (HF/HCl) and delaminated using TMAOH. However, the restacking of delaminated Ti₃CNTₓ (d-Ti₃CNTₓ) limited its surface area, restricting ion diffusion. To address this issue and enhance its energy storage potential, metal cations (Fe, Ni, Co) were intercalated using an electrostatic self-assembly method. The structural modifications through post-intercalation, confirmed through XRD, Raman, FTIR XPS, and EDX analysis, led to a significant increase in surface area, as evidenced by BET analysis. Among the intercalated MXenes, Co-Ti₃CNTₓ demonstrated the best electrochemical performance, exhibiting an expanded d-spacing of 14.25 Å and a surface area of 113 m²g⁻¹. In KOH electrolyte, Co-Ti₃CNTₓ delivered a maximum pseudocapacitance of 1470 Fg⁻¹, an energy density of 9.8 Whkg⁻¹, and a power density of 1.4 Wkg⁻¹, with outstanding cycling stability, retaining 91% capacitance over 5000 GCD cycles. This study marks the first report on metal-cation intercalation in Ti₃CNTₓ MXene, demonstrating its potential for advanced supercapacitor applications through structural engineering and metal-ion interactions.