A Multifunctional Dual-Salt Localized High-Concentration Electrolyte for Fast Dynamic High-Voltage Lithium Battery in Wide Temperature Range

摘要

In this work, a multifunctional 2m dual-salt sulfolane (TMS)/ethyl acetate (EA)-based localized high-concentration electrolyte (LHCE) with 10 wt% fluorocarbonate (FEC) is reported. Its incorporation into a Li||Ni0.5Co0.2Mn0.3O2 battery enables it to maintain nearly 89% capacity retention after 200 cycles with 1 C (200 mA g(-1)) charge/discharge current density charged to 4.6 V at 25 degrees C, showing good high-voltage cyclic stability. A superior 10 C high-rate performance with 65% (approximate to 130 mAh g(-1)) specific capacity is also achieved. Furthermore, it still remains a liquid and exhibits good ionic conductivity even at -80 degrees C, and enables Li||Ni0.5Co0.2Mn0.3O2 batteries to deliver more than 50% of their room-temperature capacity at -40 degrees C and remains stable for over 200 cycles under the same condition as before, realizing outstanding low-temperature fast-charging/discharging performance. It also demonstrates compatibility with both lithium metal and graphite anode. All in all, this work provides a new idea for the design of a fast-dynamic, high-voltage, and low-temperature lithium battery electrolyte. The findings of this work indicate that LHCEs made directly from the optimal high-concentration electrolyte are not the most suitable approach, combining the diluent with an additive is necessary and effective.