Lithium intercalation across the anatase (101) surface is investigated with hybrid DFT. It is demonstrated that the upper surface layers of the oxide are geometrically less constrained, allowing stabilization of both excess electrons (by 5 × 10–2 eV) and intercalated Li+ cations (by 1.1 × 10–1) eV compared to bulk anatase. Li+ ions tend to segregate in the first subsurface layers, forming rows along the [010] crystal direction. Also, excess electrons localize preferentially subsurface, as confirmed by these hybrid and additional random phase approximation (RPA) calculations. Furthermore, subsurface Li+ ions act as pinning centers for adsorbates, stabilizing them by roughly 1.1 × 10–1 eV, with some variations depending on the adsorption geometry and on the vicinity of the cations. The cation incorporation mechanism in the oxide is also affected by the presence of the interface: The two step Li+ insertion process has an activation energy of 1.43 eV, more than double the activation energy for cation migration in bulk systems. A monolayer of acetonitrile solvent on top of the slab facilitates the process, lowering the barrier to 7.6 × 10–1 eV. The interaction between Li+ ions and electrons is also stronger at the (101) interface and can be quantified in 9 × 10–2 eV, more than double that of its bulk value. The combined effect of adsorbate pinning and enhanced electron localization constitute a reservoir of shallow trap states in the proximity of the adsorbed donor molecules, likely to facilitate charge-transfer mechanisms. In contrast, the magnitude of the Li+/electron interaction, even if enhanced at the interface, is still low enough to allow subsequent charge migration toward other acceptor centers in the oxide, likely with a mechanism spanning different time scales.