Tailoring interfacial stability and ion kinetics via weakly-solvated fluorinated solvents for high-performance...

High-voltage lithium metal batteries (LMBs) have emerged as ideal candidates for achieving high-energy-density energy storage devices. Notably, high-reactive lithium metal and high-voltage transition metal oxide cathodes require electrolytes with superior electrochemical stability and interfacial compatibility. Herein, a solvent chemistry electrolyte design strategy is proposed that a weakly-solvated fluorinated bis(2,2,2-trifluoroethyl) carbonate (TFEC) was introduced into carbonate electrolyte for enhanced high voltage performance. The weakly solvated TFEC shows weak interaction with lithium ions, facilitating ionic transport and improving the interfacial wettability. More importantly, the thin and even TFEC-derived LiF-rich interface retards interfacial side reactions between the electrolyte and electrodes, enabling LMBs to cycle stably. Herein, the Li symmetric cells maintain stable operation for 400 h. even at a high cut-off voltage of 4.5 V, Li full cells demonstrate the excellent specific capacity of 158.1 mAh g^-1 and cycle stability with capacity retention of 90.2 % over 100 cycles. The innovative strategy of self-adapting interface design is broadly applicable, providing new insight into designing stable and high-performance LMBs.