Tension Effect Induced Ti‐O Terminals Passivation of Ti ₃ C ₂ T _x MXene Towards Self‐Discharge Suppression

ABSTRACT The self‐discharge phenomenon remains a fundamental challenge that limits the practical deployment of advanced supercapacitors, particularly in MXene‐based systems where the interfacial ion‐electron coupling dominates charge redistribution dynamics. Here, a surface terminal engineering strategy was proposed by utilizing 1,2‐bis(triethoxysilyl)ethane (BTSE) to construct a surface passivation layer through hydrogen‐bond‐mediated assembly. Benefiting from the generated tension effect between BTSE and MXene, it directly results the weakened hybridization effect between Ti atoms and surface terminal atoms, together with an upward shift of the d ‐band center and reduce of reaction energy barriers. Collectively, the passivation of surface Ti–O terminals promotes the electron transfer kinetics (Ti–O + e − + H + → Ti‐OH) and inhibits the dissociation of Ti‐OH terminal from the perspective of electron transfer coupling. As a result, the optimized MXene@BTSE electrode has effectively reduced the Ti–OH dissociation rates by 2.23‐fold and demonstrates a remarkable self‐discharge suppression, achieving 55.16% decrease of self‐discharge rate in 1 m H 2 SO 4 electrolyte, compared to the pristine MXene. Moreover, the modified MXene electrode shows around 92.43 % capacitance retention over 80 000 cycles, demonstrating excellent stability. This work establishes an electron‐structure‐property paradigm for interfacial design in electrochemical energy storage systems.