Improve the compatibility of sulfolane-graphite with the synergetic additives

Abstract

The high voltage stability (> 5.5 V) makes sulfolane (SL) an excellent electrolyte solvent candidate for high specific energy lithium-ion batteries. However, the stable solid electrolyte interphase (SEI) cannot be generated on the surface of graphite particles with SL, limiting its application. To solve the interface incompatibility, we introduce fluoroethylene carbonate (FEC) and lithium nitrate (LiNO3) in SL-based electrolyte for constructing an inorganic-rich SEI on graphite. The comprehensive characterizations and simulations demonstrate that combined effect of additives facilitates the formation of additive-derived LiF-Li3N enhanced inorganic-rich SEI. The proposed electrolyte shows stable cycling performances with 324.89 mAh/g and 97.93 % after 50 cycles in Li/graphite half-cells, compared with the capacity of 24.54 mAh/g and the capacity retention of 19.4 % in SL-without additives. Importantly, the electrolyte system obtains a capacity retention of 71 % and the capacity of (127.93 mAh/g) is higher than that without additives (110.21 mAh/g) at 4.4 V after 200 cycles. This work solves the incompatibility of SL-graphite with low-cost additives, and is beneficial to realize the commercial application of sulfolane in high specific energy batteries.