Molecular Effects of Li + -Coordinating Binders and Negatively Charged Binders on the Li + Local Mobility near the Electrolyte/LiFePO 4 Cathode Interface within Lithium-Ion Batteries.

The development of lithium-ion batteries (LIBs) is important in the realm of energy storage. Understanding the intricate effects of binders on the Li + transport at the cathode/electrolyte interface in LIBs remains a challenge. This study utilized molecular dynamics simulations to compare the molecular effects of conventional polyvinylidene difluoride (PVDF), Li + -coordinating polyethylene oxide (PEO), and negatively charged polystyrene sulfonate (PSS) binders on local Li + mobility at the electrolyte/LiFePO 4 (LFP) cathode interface. By examining concentration profiles of Li + , three different polymer binders, and anions near Li + -rich LFP and Li + -depleted FePO 4 (FP) surfaces, we found a superior performance of the negatively charged PSS on enhancing Li + distribution near the Li + -depleted FP surface. The radial distribution function and coordination number analyses revealed the potent interactions of PEO and PSS with Li + disrupting Li + coordination with electrolyte solvents. Our simulations also revealed the effects of non-uniform binder dispersions on the Li + local mobility near the cathode surface. The combined results provide a comparative insight into Li + transport at the electrolyte/cathode interface influenced by distinct binder chemistries, offering a profound understanding of the binder designs for high-performance LIBs.