Photoelectrochemical processes on metal electrodes in nonaqueous solutionsof lithium salts

The photoelectrochemical performance of lithium in a propylene carbonate so lution of LiClO4 and in a mixture of propylene carbonate with dimethoxyetha ne, as well as in a LiAlCl4 solution in thionyl chloride, has been investig ated. It has been established that when illuminating the electrodes under s tudy, electronic photoemission takes place from the metal into a passivatin g film permanently existing on the lithium surface. The measurements were i n part carried out with the Li electrode coated specially with a Li2O or Li 2CO3 protecting film. Photoemission spectroscopy has been used as a tool fo r exploring the processes of both formation and change in the composition a nd properties of the passivating layers on the lithium electrodes. The resu lts for the photoelectrochemistry of lithium have been compared with the an alogous data obtained with electrodes made of gold and SnCd alloy in a prop ylene carbonate solution of LiClO4. In the two last cases, electronic photo emission from the metal into solution has been revealed.