Computational Insights into Electrolyte-Dependent Li-Ion Charge-Transfer Kinetics at the Li_xCoO₂ Interface

Interface engineering remains a largely underexplored area and yet it holds the keys to high performance Li-ion (Li⁺) batteries. The charge transfer across electrode-electrolyte interfaces is oftentimes a significant obstacle for achieving fast charging and high power performance without compromising battery lifespan. In this work we employ a Boltzmann-averaged first-principles workflow based on constant potential and constrained density functional theory for evaluation of atomic scale factors influencing coupled ion-electron charge transfer kinetics across battery electrode-electrolyte interfaces. The approach estimates diabatic Li⁺ interface energy landscapes as function of the interface character and operational conditions and use this information to simulate charging/discharging currents. Experimental trends for the Li<i>_x</i>CoO₂ (0.5≤<i>x</i>≤1.0) electrode are reproduced for varied organic electrolytes with LiPF₆ and LiClO₄ salts, identifying Li⁺ transfer energy and Li⁺ adsorption energy as decisive factors influencing the enhanced kinetics in LiClO₄-based electrolytes over LiPF₆. The talk will conclude by comparing the performance of the aforementioned high-fidelity methods with more approximative approaches. The latter methods result in a significant computational speed-up that allows for rapid screening of liquid- as well as solid-state electrolytes with fast interface kinetics.