Effect of 15-crown-5 on the charge transfer resistance at the polymer electrolyte/modified Li-electrode interface

The effect of 15-crown-5, which is applied immediately to pure and modified surface of a lithium electrode, on the charge transfer resistance at the electrode/polymer electrolyte interface is studied. The polymer electrolyte consists of a 1: 1 mixture of oligourethan dimethacrylate and polypropylene glycol monomethacrylate (20 wt %), an initiator (azobisisobutyronitrile) (2 wt %), and a 1 M LiClO₄ solution in gamma-butyrolactone (78 wt %). The conductivity of this gel electrolyte is 3 × 10^?3 S cm^?1. The temperature dependence of the impedance of the Li/gel electrolyte/Li electrochemical cells is measured for electrodes of four types. The activation energies for the charge transfer at the Li/electrolyte interface are calculated. It is found that, after treating the test lithium electrodes with 15-crown-5, the charge transfer resistance decreases, and in the case of the modified lithium surface, the activation energy for the process decreases by 1.8 times.