Replacing a dilute 1 M LiPF6-based electrolyte with a hydrofluoroether (HFE)-modified highly concentrated electrolyte (HCE) stabilizes the Li metal interface and results in higher discharge capacity, Coulombic efficiency, and thermal stability.
Significance and Impact
This study demonstrates that HCEs can be used with lithium metal anode and a high capacity cathode to improve the thermodynamic stability as well as the thermal stability of the electrolyte. Furthermore, replacing LiPF6 with a concentrated electrolyte can possibly mitigate some of the safety concerns regarding HF formation.
- The HCE mitigates the formation of dendrites and/or an inhomogeneous degradation layer as seen using SEM imaging.
- The higher thermodynamic stability of the HCE against Li metal, as demonstrated through lower resistivity using electrochemical impedance spectroscopy, leads to higher discharge capacity and Coulombic efficiency.