Synthesis of Lithium Sulfide by Cold Plasma Method and Its Energy Storage Properties

Lithium sulfide was produced in a plasma system by the reaction of plasma-ionized sulfur with lithium metal. Thermodynamic calculations and optical emission spectroscopy were used to investigate the chemical behavior and reaction mechanism of lithium metal in sulfur plasma atmosphere. The effects of radiofrequency (RF) power and radiofrequency (RF) time on the properties of lithium sulfide prepared by the cold plasma method were investigated. The macroscopic morphology, microscopic morphology, elemental distribution and phase of the sulfide product (lithium sulfide) were further tested and analyzed. The results show that under the conditions of power ≥ 210 W and time ≥ 15 min, Li₂S₂-free lithium sulfide with high purity is generated; with the enhancement of power, lithium oxide is transformed into lithium sulfide. Subsequently, its electrochemical performance as a battery anode was tested. The test obtained: the specific capacity of charging is up to 216.9 mAh/g, and the specific capacity of discharging is up to 182.8 mAh/g; the impedance has a double capacitance to resist arcing, which can be carried out normally in the charging and discharging process, and it has a certain degree of electrochemical performance.