Аннотация:The structure of electrified interfaces of solid electrodes with electrolyte solutions based on aprotic solvents, specific features of kinetics and mechanism of processes that are realized on such interfaces are of an important direction of fundamental electrochemistry and electrochemical material science. It is well-known that the quantity of reliable data on the electrical double layer (EDL) structure sharply decreases when one transfers from the classical mercury-like metals and alloys to the metals that are widely used in practice (Fe, Ni, Cr, Al). This is explained by substantial methodic difficulties caused by the necessity of preparing surfaces that are free of oxide layers.
As to Al electrode is concerned, we can confirm that the substantial progress was reached when we used the method of measurements on electrodes with in situ renewable surface. Mechanical renewal by cutting of the thin metal layer (~10 m) immediately in the electrolyte solution allows one to prevent the contact of metal with atmosphere and carry out measurements against the well reproducible initial state of the electrode surface. In pioneer works [1, 2] we managed to obtain reliable and well reproducible data on the EDL structure on Al electrode in surface inactive electrolytes in dimethylsulfoxide, dimethylformamide and –butyrolactone.
In our presentation, we develop these investigations and analyze new data obtained on Al electrode in tetraalkylammonium salts in propylenecarbonate. Using cyclic voltammetry, chronoamperometry and electrochemical impedance methods, potential regions where Al electrode can be considered as closed to the ideal polarizable electrode were established. From the position of capacity minimum in the diluted solutions of tetraalkylammonium salts, zero charge potentials of Al in the studied solutions were found. Dependences of the EDL charge vs. potential were calculated. We considered, as well, the influence of water additions on experimental dependences.
The authors thank the Russian Foundation of Basic Research (grant no. 18-03-00616) for the financial support of this work.
Literature
1. Safonov V.A., Sokolov S.A. // Soviet Electrochemistry. 1991. V. 27. P. 1161.
2. Safonov V.A., Sokolov S.A. Gerovich V.M., Choba M.A. // Doklady Akademii nauk SSSR. 1988. V. 299. P. 1438.