Photoelectrochemical currents and noises on a lithium electrode

The spectra of a photoelectrochemical current on a lithium electrode in γ-butyrolactone, propylene carbonate, dimethylsulfoxide solution with LiClO4 and LiBF4 were investigated. The threshold energy of electron photoemission Eth from lithium to the oxide film were compared; we obtained, as a result, that Eth = 1.3−1.4 eV for the different electrolytes. The value of the intensity of the electric field in the oxide film under stationary conditions was 1 × 107−3 × 107 V/m. It was found that, under a strong illumination of electrode by sunlight radiation, the value of the photo-electromotive force and the electrochemical noise increases. By the analysis of the kinetics of this photoeffect and noise we concluded that the migration of photogenerated carriers through the oxide film is a limiting stage of its transfer process. The velocity constant of this reaction was Ks = 1 × 102−2 × 102 s−1.