Cation-Intercalated Pillared Carbide (Mo2TiC2Tx) and Carbonitride (Ti3CNTx) MXenes for Superior Energy Storage Application

Abstract

This study presents a comprehensive methodology for the etching and delamination of carbide (Mo₂TiC₂Tₓ) and carbonitride (Ti₃CNTₓ) MXenes, alongside protocols for the intercalation of alkali and alkaline earth metal ions (Li⁺, Na⁺, K⁺, Mg²⁺) into these materials. Post-intercalation, the resulting composites exhibit exceptional performance as supercapacitor electrode materials, with K⁺-intercalated Ti₃CNTₓ demonstrating an ultra-high capacitance of 1530 F g⁻¹ and K⁺-intercalated Mo₂TiC₂Tₓ achieving 698 F g⁻¹ at a scan rate of 2 mV s⁻¹. Moreover, the intercalation of cations enhances charge storage kinetics by extending charge/discharge times and reducing solution resistance and charge transfer impedance, indicative of improved ion transport pathways. Structural analysis reveals a significant increase in the c-lattice parameter and interlayer d-spacing, attributed to the effective accommodation of cations within the MXene framework. These findings underscore the potential of cation intercalation for tailoring MXene properties, offering a pathway for the design of advanced energy storage materials with remarkable electrochemical performance.