Selenium vacancies activating MnCoSe2@MnCo−LDH Mott−Schottky interfaces with rapid redox kinetics for hybrid supercapacitors

Tailoring interfacial electronic structures through Mott–Schottky (M−S) heterojunction design offers a powerful route to optimize charge transport dynamics. Herein, we propose a Se defect-mediated synergistic regulation strategy to construct M−S heterojunctions by introducing Se vacancies (V Se ) into MnCoSe 2 @MnCo–LDH (MnCoSe 2 @LDH) composites, thereby modulating interfacial charge redistribution. Strategically, a controlled in situ semi-transformation first establishes a robust heterointerface to induce strong interfacial electronic coupling, while a subsequent reduction step precisely creates Se vacancies to maximize electroactive sites. Density functional theory calculations verify that Se vacancies impart metallicity and optimize the water adsorption energy to a thermodynamically ideal level of −0.81 eV (representing a 22.1% reduction in binding strength relative to the vacancy-free heterojunction). This moderate binding effectively bridges the gap between the insufficient affinity of pristine LDH (−0.43 eV) and the excessive trapping of vacancy-free counterparts (−1.04 eV), enabling rapid redox kinetics. Consequently, the synergy of M − S interfaces and defect engineering boosts the specific capacity from 940 C g −1 to 1025 C g −1 at 1 A g −1 . The hybrid supercapacitor V Se –MnCoSe 2 @LDH/NF//AC delivers 92 Wh kg −1 at 800 W kg −1 and maintains 88.9% capacitance retention after 10,000 cycles. This study highlights a precision interface engineering route for high-performance energy storage.