Tailoring the lithium-ion solvation sheath via bioinspired Zein/Lysine additives: a combined spectroscopic and molecular dynamics study

The high Li⁺ desolvation barrier and uncontrolled ion-pair aggregation in conventional carbonate electrolytes severely limit the performance of lithium metal batteries. Inspired by biological ion channels, we propose a biomimetic dual-additive strategy employing zein (corn protein) and lysine to regulate the Li⁺ solvation environment. Molecular dynamics simulations and spectroscopic analyses reveal that lysine competitively enters the primary solvation sheath, displacing carbonate solvents, while zein amide groups further modulate the solvation architecture. This restructuring forms a unique “clustered yet conductive” solvation architecture, in which lysine bridges confine PF₆^- anions within dynamic aggregates, significantly suppressing anion mobility and elevating the Li⁺ transference number to 0.88. The architecture simultaneously lowers the interfacial desolvation barrier and facilitates the formation of a robust, dendrite-suppressing solid electrolyte interphase derived from the bio-additives. Consequently, the lithium metal anode delivers stable cycling for over 600 h, and the Li||LiFePO₄ (LFP) full cell retains approximately 87% capacity after 500 cycles at 0.5C. This work demonstrates a sustainable solvation-engineering paradigm based on abundant biomolecules, highlighting the concept of “clustered yet conductive” coordination for next-generation high-energy–density batteries.