Enhanced Charge-Transfer Kinetics Enabled by ZrO2–Based Dielectric Layers in Lithium-Ion Batteries

The development of high-rate capability lithium-ion batteries (LIBs) requires suppression of charge-transfer resistance (RCT) at electrode–electrolyte interfaces. Here, zirconia-based dielectric oxides (MZ; M = Y, Gd, Sm, Er, etc.) were introduced onto LiCoO2 (LCO) surfaces as electronically and ionically insulating modifiers to accelerate interfacial ion transport. Electrochemical impedance spectroscopy showed that Y2O3 modified ZrO2 (YZ) decoration reduced RCT from 75.8 Ω in reference LCO to 38.3 Ω, accompanied by a 2.3-fold improvement in capacity retention at 20C. Density functional theory molecular dynamics (DFT–MD) simulations showed that solvated Li ions coordinate with surface oxygen atoms in discharging, and that adsorption energies are governed by local charge distributions determined by stabilizing cations. Optimal adsorption activity, and thus the lowest RCT, occurred when the surface charge corrugation was balanced. These findings provide design principles for dielectric interface engineering to enhance rate capability of LIBs.