The Effect of 15-Crown-5 and Benzo-15-Crown-5 on the Performance of Lithium Batteries in LiPF6 and LiN(CF3SO2)2 Electrolytes

The reversibility of electrode reactions in Li//LiFePO4 cells with two liquid electrolyte compositions modified by 15-crown-5 and benzo-15-crown-5 is tested. By cycling Li//LiFePO4 batteries, it is shown that crown ethers enhance the stability of discharge capacity and Coulomb efficiency in both electrolytes: 1 М LiPF6 in ethylene carbonate/dimethyl carbonate (1 : 1) and 1 M LiN(CF3SO2)2 in dioxolane/dimethoxyethane (2 : 1), which differ by their ability to form solid-electrolyte layers on the electrode surface. The energy of Li+-ion transport through the layer of crown ethers under study is modeled by quantum-chemical methods. The conclusions of quantum chemical calculations well agree with the results of electrochemical measurements.