Interface-Targeting Individually Functionalized Ionic Additive to Construct Stable Interphase on Selective Electrode Surface for Practical Lithium-Ion Pouch Cells

Individually functionalized cation- and anion-based ionic additives are designed to mitigate the interfacial side reaction occurring on both the positive and negative electrode surfaces. By applying 1-phenyl-1H-imidazole-3-ium trifluoromethanesulfonate as a surface-targeting electrolyte additive, the reciprocal failure from multiple electrolyte addition applications is theoretically prevented. Selective interface modification is performed using ionic additives by the migration of cations and anions to the negative and positive electrode surfaces, respectively. A drastic improvement in cycleability compared with that by a general carbonate electrolyte is achieved because the reinforcement of both the graphite and LiNi_0.8Co_0.1Mn_0.1O₂ electrode surface is possible by ionic additives. Moreover, a further improvement in the cycle performance compared with that by the typical solid electrolyte interphase-forming additives, such as vinylene carbonate and fluoroethylene carbonate, is demonstrated by the ionic additive.