A weakly-solvated ether-based electrolyte for fast-charging graphite anode

Weakly-solvated electrolytes（WSEs） utilizing solvents with weak coordination ability offer advantages for low-potential graphite anode owing to their facile desolvation process and anions-derived inorganic-rich solid electrolyte interphase（SEI） film. However, these electrolytes face challenges in achieving a balance between the weak solvation affinity and high ionic conductivity, as well as between rigid inorganicrich SEI and flexible SEI for long-term stability. Herein, we introduce 1,3-dioxolane（DOL） and lithium bis（trifluoromethanesulfonyl）-imide（Li TFSI） as functional additives into a WSE based on nonpolar cyclic ether（1,4-dioxane）. The well-formulated WSE not only preserves the weakly solvated features and aniondominated solvation sheath, but also utilizes DOL to contribute organic species for stabilizing the SEI layer. Benefitting from these merits, the optimized electrolyte enables graphite anode with excellent fastcharging performance（210 mAh/g at 5 C） and outstanding cycling stability（600 cycles with a capacity retention of 82.0% at room temperature and 400 cycles with a capacity retention of 80.4% at high temperature）. Furthermore, the fabricated Li Ni0.8Co0.1Mn0.1O2||graphite full cells demonstrate stable operation for 140 cycles with high capacity retention of 80.3%. This work highlights the potential of tailoring solvation sheath and interphase properties in WSEs for advanced electrolyte design in graphite-based lithium-ion batteries.