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Reaction products in electrochemical processes can be identified by coupling an electrochemical thin-layer flow cell to a thermospray mass spectrometer. The performance of this analytical method, electrochemical thermospray mass spectrometry, is demonstrated. This includes the characterization of the improved electrochemical thin-layer flow cell. This cell offers the possibility to combine cyclic voltammograms with mass spectrometry. This goal was achieved, too, by the construction of a new thermospray ion source and a special vacuum recipient.

Using differential electrochemical mass spectrometry, we determined the amount of H2‐evolution occuring during formaldehyde oxidation as a function in the potential region of the first oxidation wave. In the second wave, the oxidation product is CO2 in pH 8 solution, as opposed to more alcaline solutions where only formiate is formed. Formaldehyde is reduced to methanol at potentials negative of the RHE.—An electrochemical formaldehyde sensor was built with a sensitivity below 1 ppm. Cross sensitivities towards alcohols can be lowered by UPD of Ag or Hg.

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We have investigated an inorganic lithium battery system in which LiCoO 2 is used as the positive electrode and lithium, intercalated into graphite, serves as negative electrode. The conducting salt is lithium tetrachloroaluminate (LiAlCl 4 ). The electrolyte is based on SO 2 . It has been shown that a layer of lithium hydroxide is present on the surface of the lithium cobalt oxide. This has a negative impact on the stability of the electrode. To improve stability, we have developed a purification process for removing the lithium hydroxide from the surface of the positive electrode. After purification the cells show no significant change in either capacity or internal resistance when cycled. Up to 70% of the theoretical capacity of electrodes which have been purified in this way can be used without any negative effects being observed. To prevent the deposition of metallic lithium leading to a hazardous situation, a new safety concept was developed whereby local short circuits are allowable. Safe functioning of the new concept has been demonstrated with tests on complete cells.