Advanced Nonflammable Localized High-Concentration Electrolyte For High Energy Density Lithium Battery

The key to realize long-life high energy density lithium batteries is to exploit functional electrolytes capable of stabilizing both high voltage cathode and lithium anode. The emergence of localized high-concentration electrolytes (LHCEs) shows great promise for ameliorating the above-mentioned interfacial issues. In this work, a lithium difluoro(oxalate)borate (LiDFOB) based nonflammable dual-anion LHCE is designed and prepared. Dissolving in the mixture of trimethyl phosphate (TMP) /1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether (D-2), the continuously consumption of LiDFOB is suppressed by simply introducing lithium nitrate (LiNO3). Meantime, as most of the TMP molecular are coordinated with Li+, the electrolyte does not show incompatibility issue between neither metal lithium nor graphite anode. Therefore, it demonstrates excellent capability in stabilizing the interface of Ni-rich cathode and regulating lithium deposition morphology. The Li||LiNi0.87Co0.08Mn0.05O2 (NCM87) batteries exhibit high capacity retention of more than 90% after 200 cycles even under the high cutoff voltage of 4.5 V, 1 C rate. This study offers a prospective method to develop safe electrolytes suitable for high voltage applications, thus providing higher energy densities.