Electrolyte Microenvironment Evolution and Interphase Formation: Coordination Dynamics, Electric Double Layers, Reactive Transport, Film Growth, Mechanics, and Evidence

Electrolyte microenvironments evolve through coupled changes in ionic coordination, electric-double-layer structure, reactive transport, phase selection, interphase growth, mechanical damage, regeneration, and preparation history. We formulate these processes as a thermodynamically consistent coordination–transport–reaction graph coupled to continuum fields and explicit observation operators. The framework establishes nonnegativity, simplex invariance, elemental, mass, and charge conservation, together with a single-counted free-energy–power–dissipation identity. It covers singular Maxwell–Stefan cross-diffusion, vacuum-degenerate mobility, countable coordination and film-phase registries, conservative topology events, diffuse-to-sharp interface limits, morphology-dependent effective transport, and rupture–exposure–reaction–regeneration cycles. Counterexamples identify the limits of unrestricted stability, rank-changing transport, and topology continuation. Reproducible analytic and numerical benchmarks verify the declared mathematical branches without parameter refitting. A unified multimodal observation framework connects the evolving state to Raman, NMR, XPS, EQCM, EIS, gas, and film-thickness measurements. Structural and practical nonidentifiability are explicitly distinguished, and residual-history fields are accepted only after independent held-out improvement over simpler mechanisms. A traceable real-experiment evidence gate combines frozen parameters, independent calibration, replicate covariance, familywise error control, and held-out lack-of-fit testing. The resulting inference is an evidence-qualified class of admissible mechanisms rather than an automatically unique microscopic narrative. Subject to successful passage through this frozen multimodal gate, the framework provides a rigorous account of the microscopic mechanisms governing electrolyte evolution and interphase formation. Keywords **electrolyte microenvironment; solvation and coordination dynamics; electric double layer; reactive transport; Maxwell–Stefan diffusion; solid–electrolyte interphase; phase selection; film growth; fracture and regeneration; multimodal characterization; mechanism identifiability; experimental validation**