Dual-additive enabled inorganic-rich solid electrolyte interphase for high-rate lithium negative electrodes

Constructing a robust, highly conductive solid electrolyte interphase is the key to unlock the high-rate potential of lithium negative electrodes for broad applications. Here we propose a simple yet effective strategy, by introducing a sulfur-containing compound and LiNO₃ as dual additives into a conventional carbonate electrolyte. As an example, 3-sulfolene is found to enhance the dissolution of LiNO₃, and it works with NO₃^- to regulate the Li⁺-solvation structure and facilitate the formation of a robust while uniform solid electrolyte interphase rich in Li₃N/Li₂S/Li₂O inorganics, enabling rapid Li⁺ transfer and high interfacial stability. Consequently, Li | |LiFePO₄ cells achieve 81.7% capacity retention after 6,000 cycles at 80 C, while Li | |LiNi_0.8Co_0.1Mn_0.1O₂ cells maintain 81.3% capacity after 500 cycles at 10 C. Moreover, two pouch cells with specific energy exceeding 500 Wh kg^-1 (calculated based on total mass of the pouch cells) retain 92.1% and 91.8% of initial capacities after 143 and 149 cycles (charged at 0.1 C and discharged at 0.3 C), respectively. This work provides a general dual-additive strategy to promote the formation of an inorganic-rich solid electrolyte interphase for high-rate lithium negative electrodes.