Electrolyte solvation regulation engineering promotes Li-SPAN battery without esters

Electrolyte plays a crucial role in the construction of electrode interfaces of high energy lithium metal battery systems. For advanced Li-SPAN battery system, the forbidden of shuttle effect in traditional carbonate electrolyte is attributed to the formation of the cathode/electrolyte interface (CEI). Unfortunately, the inherent electrochemical instability of Li metal in carbonate electrolyte limits its commercialization. Herein, a novel carbonate-free weakly solvating siloxane electrolyte is presented and applied in Li-SPAN battery system for the first time. The anion derived electrode/electrolyte interfaces ensure excellent electrochemical performance which enables high Li plating/stripping Coulombic efficiency of 99.63 % in Li||Cu cells and long lifespan over 400 h under critical condition of 5 mAh cm−2, where 30 µm Li foil is used with totally ca. ∼6 mAh cm−2 in symmetric cell. Meanwhile, no shuttle effect occurs on the SPAN cathode and the kinetics of CEI is promoted. The Li-SPAN battery exhibits prolonged cycling stability over 500 cycles with a capacity retention of 96.8 %. Furthermore, the 0.2 Ah pouch cell shows stable cycling performance with capacity retention of 92.4 % over 20 cycles. This work provides a new approach for high energy Li-SPAN battery without carbonate electrolytes.