Elimination of Rate-Induced Graphite Exfoliation and Li Plating in Benchmark-Exceeding Battery Electrolytes

Abstract

Lithium-ion batteries (LIBs) face untenable reductions in cycle life under extreme fast-charging (XFC) conditions, which primarily originate from a variety of kinetic limitations between the graphite anode and the electrolyte. Through quantitative Li+ loss accounting and comprehensive materials analyses, it is directly observed that the operation of LIB pouch cells at 4 C||C/3 (charging||discharging) results in Li plating, disadvantageous solid-electrolyte-interphase formation, and solvent co-intercalation leading to interstitial decomposition within graphite layers. By employing a designed ester-based electrolyte, the capacity retention of these cells improved from 55.9% to 88.2% after 500 cycles when operated at the aforementioned conditions. These metrics are the result of effective mitigation of these failure modes due to superior Li+ transport and desolvation characteristics demonstrated through both experimental and computational characterizations. This work reveals the vital nature of electrolyte design to XFC performance. Figure 1