Problems of corrosion and other electrochemical side processes in lithium chemical power sources with non-aqueous electrolytes

Abstract

The following electrochemical side processes were studied: (i) electrochemical corrosion processes in a short-circuited couple of active cathode material (FeS 2)-current-collector material (ii) electrochemical and chemical decomposition of non-aqueous electrolytes proceeding in parallel with the base electrochemical reaction in power sources with a working discharge voltage of 1.5 V. The dynamics and direction of corrosion processes in the couple of FeS 2-current collector depend on the potential difference between the active cathode substance and the current-collector material and on the overvoltage value of conjugated electrochemical processes. In the case of a starting unreduced cathode, the reduction process takes place on pyrite and the oxidation process occurs on the current collector. After a partial cathode reduction the process direction changes. The rate of decomposition of the electrolyte in the potential range of 1.5 V is determined by its composition, the conditions of its, preparation and purification, and the cathode material used as catalyst in the process of the decomposition of the electrolyte.