Molecular Engineering of Organic Prelithiation Agents via Frontier Orbital Regulation

Replenishing the irreversible depletion of the active lithium inventory in lithium-ion batteries is critical for enhancing both energy density and cycling stability in practical applications. Existing prelithiation strategies predominantly address SEI-derived lithium depletion during initial cycles but remain inadequate against subsequent active lithium loss induced by dynamic SEI reconstruction during prolonged cycling. Here, we report a molecular engineering strategy that leverages frontier orbital regulation in organic lithium salts to enable staged, potential-dependent lithium release. By introducing electron-withdrawing or electron-donating functional groups, the HOMO energy levels of molecules are precisely regulated, enabling customized tuning of the decomposition potential for lithium salts. Through this strategy, the reactivity of individual functional groups can be selectively activated. Consequently, a novel multiplatform organic prelithiation agent (Li₄DOPA) has been synthesized. Comprehensive analyses elucidate potential-dependent decomposition behavior governed by the electronic structure. Benefiting from this molecular-level control and the independent delithiation behavior of distinct functional groups, Li₄DOPA enables stepwise lithium release when coupled with LiFePO₄ cathodes. The additional lithium compensates for losses in graphite and SiO_<i>x</i>/C anodes, ultimately doubling the cycle life. This work establishes generalizable guidelines for developing advanced functional prelithiation agents through targeted frontier orbital engineering.