Composition and working principle of lithium-sulfur battery

Composition and working principle Sulfur is a yellow solid in the form of an S8 ring. The high energy density and high specific capacity of lithium-sulfur batteries are caused by the breaking and recombination of s-s bonds in S8 molecules. At present, most of the positive electrode data of lithium-sulfur batteries is obtained by combining sulfur with porous carbon data, carbon nanotubes, graphene, metal oxides, conductive polymers, etc., while the negative electrode data is obtained by lithium sheets. The electrochemical reaction principle of lithium-sulfur battery: S8+16Li2→8Li2S. During the discharge process, the metal lithium anode (negative electrode) is oxidized to form lithium ions and electrons. Lithium ions move to the cathode through the electrolyte, and electrons reach the cathode (positive electrode) through the external circuit wire. At the positive electrode, sulfur reacts with lithium ions and electrons to form lithium sulfide. The charging process is just the opposite. From the detailed reflection process and discharge process, the sulfur first lithium forms a series of long chain center lithium sulfide (S8→)Li2S8→Li2S6→Li2S4). This long chain substance is simply dissolved in the ether electrolyte, and the long chain The remaining sulfur in the battery accounts for 25% of the total capacity. When the remaining sulfur is further petrified, the dissolved long-chain polysulfides are decomposed into short-chain sulfides (Li2S4→Li2S2→Li2S). The solubility of lithium sulfide is insufficient, and some solid substances are deposited on the electrode. In this process, sulfur accounts for 75% of the total sulfur. All in all, as the discharge process progresses, the internal raw materials of the lithium-sulfur battery undergo the transformation of three conditions of solid-liquid-solid. The transportation of lithium ions during the entire discharge process of traditional lithium batteries is very different. Disclaimer: Some pictures and content of articles published on this site are from the Internet, please contact to delete if there is any infringement.