Unveiling the Facet-Dependent Interfacial Chemistry and Kinetics in Nanostructured Anatase TiO2 for Li+ Storage

Abstract

Titanium dioxide (TiO₂), while being an affordable and stable anode material for Li-ion batteries, suffers from limited Li⁺ insertion kinetics. To overcome this, we comprehensively investigate the facet-dependent electrochemical dynamics by synthesizing three distinct single-crystal anatase TiO₂ morphologies (cubic, truncated, and octahedral) with controlled exposure of {001}, {100}, and {101} facets. Combined electrochemical characterizations, rate testing, diffusion coefficient analysis, impedance spectroscopy, and postcycling structural probes reveal that morphologies enriched in high-energy {001} and {100} facets, cubic and truncated, show enhanced reversible capacity retention and higher effective Li⁺ diffusion coefficients compared with octahedral particles dominated by {101} facets. We show that these improvements arise from surface stabilization and less parasitic reactions. Beyond titania, this work establishes a transferable, materials-centric approach, facet-controlled synthesis coupled with multimodal electrochemical and structural interrogation, for isolating and understanding structure–transport relationships in any emerging electrode materials. These mechanistic insights reframe facet engineering as an active strategy for designing high-rate, long-life intercalation electrodes.