| 초록 |
To improve the performance of lithium-ion battery (LIB), various studies have been developing functional binders to reduce the electrolyte/electrode interfacial impedance, Rint. Here, we utilized molecular dynamics (MD) simulations to characterize Li+ transport at the liquid electrolyte/LiFePO4 (LFP) cathode interface and the molecular effects of functional binders. Compared with conventional poly(vinylidene fluoride) (PVDF), Li+-coordinating or negatively charged polymers can lower the Li+ free energy at interface and effectively reduce Rint. Yet, the reduction of Rint may be limited by the polymer chain rigidity. From non-equilibrium MD, we identified three sub-interfacial regions during the Li+ (de-)intercalation: conventional Stern and diffusive layers, and a unique Li+ depletion region. Analyses suggest that the concentration gradient and the electric field drive the Li+ transport in the Stern and diffusive layers but not in the depletion region. The combined results suggest that improving the Li+ affinity and the local mobility at interface can reduce Rint, where the free energy and electric potential variations play dominant roles. |
