Interlayer Covalent Reinforcement-Enabled Lattice Reprogramming for Durable Capacitive Deionization

Capacitive deionization (CDI) offers a low-energy route for desalination but is hindered by electrodes lacking both high ion storage and durability. Here we present a covalently supported interlayer engineering strategy that transforms layered molybdenum sulfide (MoS₂) into a high-performance electrode with exceptional capacity and stability. By precisely intercalating butane-1,4-diol, we replace weak van der Waals interactions with rigid covalent linkages, simultaneously expanding interlayer spacing and inducing local 2H-to-1T lattice reconstruction. This dual structural reprogramming fundamentally reconfigures Mo-S orbital hybridization, generating high-energy antibonding states that promote strong Na⁺ chemisorption while preventing framework collapse. Consequently, the engineered electrode delivers an ultrahigh salt removal capacity of 77.4 mg g^-1, over threefold higher than pristine MoS₂, without measurable decay over 50 cycles, and demonstrates scalable brine treatment outperforming state-of-the-art 2D electrodes. This work establishes a generalized paradigm for covalently reinforced 2D frameworks, resolving the long-standing performance-stability paradox in CDI and advancing practical, high-capacity desalination.