Our new paper in Advanced Science (IF: 14.3) "High-Entropy Non-Flammable Ionic Liquid/Dimethoxymethane Composite Electrolyte for High-Performance Lithium-Ion Batteries"

The development of high-energy-density and high-safety lithium-ion batteries requires advancements in electrolytes. The state-of-the-art carbonate electrolyte faces challenges for operation at high voltage and has low thermal stability. This study proposes an ionic liquid/ether composite high-entropy electrolyte that consists of N-propyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PMP–TFSI) ionic liquid, dimethoxymethane (DME), lithium difluoro(oxalato)borate (LiDFOB), fluoroethylene carbonate (FEC), and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE). In this electrolyte, a unique coordination structure forms, where Li+ is surrounded in a high-entropy environment consisting of DME, FEC, TTE, TFSI–, DFOB–, and PMP+. The effects of this solution structure on the solid-electrolyte interphase chemistry and Li+ desolvation kinetics are examined. The proposed electrolyte has low flammability, high thermal stability, negligible corrosivity toward an Al current collector, and ability to withstand a high potential of up to 5 V without showing a significant side reaction current. Importantly, this electrolyte is highly compatible with graphite and SiOx anodes, as well as a high-nickel LiNi0.8Co0.1Mn0.1O2 cathode. Operando X-ray diffraction data confirm that the co-intercalation of DME and PMP+ into the graphite lattice, a long-standing challenge, is eliminated with this electrolyte. Graphite, SiOx, and LiNi0.8Co0.1Mn0.1O2 electrodes all exhibit better rate capability and cycling stability in the proposed electrolyte compared to those measured in a conventional carbonate electrolyte. A 4.5-V LiNi0.8Co0.1Mn0.1O2//graphite full cell with the proposed high-entropy electrolyte is shown to have superior specific capacity, rate capability, and cycling stability, demonstrating the great potential of the proposed electrolyte for practical applications.