Effect the temperature and lithium polysulfides on the composition of lithium cathodic deposits formed on a steel electrode

Using our method developed earlier, we studied the effect the lithium polysulfides on the amount and ratio of electrochemically active metallic lithium, electrochemically inactive metallic lithium, and chemically formed lithium compounds into cathode deposits formed on a stainless steel electrode during galvanostatic cycling in 1М solution of LiClO4 in sulfolane at 15, 30, 45 and 60°C. It is shown that an increase in temperature leads to an increase in the Coulomb efficiency of cycling and the amount of electrochemically active metallic lithium and a decrease in the amount of electrochemically inactive metallic lithium, regardless of the presence of lithium polysulfides into electrolyte. When lithium polysulfides are introduced into the electrolyte, an increase in the Coulomb efficiency of metallic lithium cycling and a change in the ratio of various forms of lithium in cathode deposits towards an increase in electrochemically active lithium by about 1.5 times are observed. It is assumed that lithium polysulfides contribute to the dissolution of electrochemically inactive metallic lithium, forming on the electrode an interface “sulfide” film with high ionic conductivity and good protective properties, especially at elevated temperatures.