Competitive Solvation-Induced Concurrent Protection on the Anode and Cathode toward a 400 Wh kg-1 Lithium Metal Battery

The unstable electrode/electrolyte interface is one of the key obstacles for practical Ah-level Li metal batteries, but an efficient approach that can construct a stable interface on both a cathode and an anode simultaneously is lacking. Herein, on the basis of a strategy for regulating electrolyte solvation chemistry, fluoroether as a destabilizer is introduced to disturb the Li+ solvation sheath and weaken the interaction between Li+ and carbonyl of carbonate-based solvents, which renders recrystallization of LiPO2F2 from the electrolyte for concurrent surface protection on both the anode and the cathode. Decomposition of LiPO2F2 forms Li3PO4 and LiF, which rebuild the electrode/electrolyte interface and prevent oxidation of carbonate solvent under a high voltage of 4.6 V. Using this strategy, the Li symmetrical cell can sustain 10 mAh cm(-2) Li stripping/plating for 1000 h; a 3.62 Ah pouch cell of Li/Li-rich layered oxide with a N/P ratio of 2.0 and an electrolyte injection ratio of 2.49 g/Ah exhibit an ultrahigh energy density of 430 Wh kg(-1) and an extended lifespan.

Automated summary

This study introduces a strategy based on regulating electrolyte solvation chemistry, using fluoroether as a destabilizer to construct a stable interface on both the cathode and anode simultaneously. Through this method, surface protection of lithium metal batteries and improved battery performance can be achieved.