Enhanced Electrolyte Transport and Kinetics Mitigate Graphite Exfoliation and Li Plating in Fast-Charging Li-Ion Batteries

Despite significant progress in energy retention, 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. It is found that these failure modes originate from the insufficient properties of conventional electrolytes, where employing a designed ester-based electrolyte improved the capacity retention of these cells from 55.9% to 88.2% after 500 cycles when operated at the aforementioned conditions. These metrics are the result of effective mitigation of the aforementioned failure modes due to superior Li+ transport and desolvation characteristics demonstrated through both experimental and computational characterization. This work reveals the vital nature of electrolyte design to XFC performance.

Automated summary

By analyzing quantitative Li+ loss and conducting comprehensive materials analyses, it is found that lithium-ion batteries experience significant reductions in cycle life under extreme fast-charging conditions. The failures result from kinetic limitations between the graphite anode and the electrolyte. The use of a designed ester-based electrolyte improves capacity retention and mitigates failure modes, highlighting the vital role of electrolyte design in fast-charging performance.