Alloy formation processes at electrochemical intercalation of lithium into intermetallic compounds of magnesium with zinc

A comparative study of alloy formation processes that occur during the electrochemical intercalation of lithium from lithium chloride solutions in dimethylformamide into intermetallic compounds of magnesium with zinc (MgZn₂, Mg₂Zn₃) and the corresponding individual metals is studied by chronopotentiometric and voltammetric methods. Lithium-containing phases are formed in all samples studied; moreover, for MgZn₂ and Mg₂Zn₃ electrodes, the phases formed are preferentially in the Li-Zn system. The largest number of lithium-containing phases is formed in zinc. It is shown that the electrochemical behavior of intermetallic electrodes is associated with their nature, where a single alloy component plays the key role, namely, zinc for MgZn₂ and magnesium for Mg₂Zn₃. The cathodic intercalation of lithium into MgZn₂ is characterized by anomalously low polarizability as compared with the other electrodes. The lithium extraction coefficient K _ex ^Li increases from the first to the tenth cycle for all electrode studied. The highest K _ex ^Li are typical of Zn and the lowest are typical of Mg₂Zn₃.