Li+ Solvation Shell Speciation (2D)

A molecular-scale look at what "electrolyte engineering" actually rearranges: the shell of solvent and anions around each lithium ion. This 2D particle simulator runs Li⁺ ions, FSI⁻ anions, coordinating solvent molecules and an inert fluorinated diluent under excluded-volume repulsion plus Coulomb-like ion attraction and solvent-coordination forces, so contact ion pairs (CIP), solvent-separated ion pairs (SSIP) and aggregates (AGG) emerge on their own from particle positions rather than being faked from a formula. Raise the diluent fraction and watch the population shift toward CIP/AGG as the effective dielectric screening drops — the exact mechanism localized high-concentration electrolytes (LHCE) use to enable fast lithium-ion charging with a thinner, more anion-derived SEI. A running history strip shows the same speciation shift unfolding over time.