Ti3C2Tx MXene Electrode Capacitance Enhancement via Molecular Spacer Intercalation and Surface Termination Engineering

This study investigates gravimetric and volumetric capacitance enhancement in Ti3C2Tx MXene electrodes via molecular spacer intercalation and surface termination ratio control within the context of electrochemical energy storage and 2D materials science, an area of growing scientific importance given its implications for high-power-density storage for electric vehicles, portable electronics, and grid ultracapacitor banks. Using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy in 1M H2SO4 electrolyte under N2 atmosphere, we examine intercalated spacer molecules expanding interlayer d-spacing, facilitating proton access to electroactive Ti surface sites and increasing effective double-layer capacitance in 28 MXene electrode variants across 5 spacer molecule types and 3 surface termination conditions tested at scan rates 5-500 mV/s drawn from nitrogen-atmosphere electrochemical cell at room temperature with 1M H2SO4 as electrolyte. Results indicate that DMSO-intercalated, fluorine-reduced Ti3C2Tx achieves gravimetric capacitance of 612 F/g at 5 mV/s with 84% retention at 100 mV/s and 91% capacity after 10,000 cycles (p < 0.001), with 612 F/g capacitance, 54.2% improvement over unmodified MXene as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to electrochemical energy storage and 2D materials science and carry actionable implications for the design of programs and policies targeting high-power-density storage for electric vehicles, portable electronics, and grid ultracapacitor banks.