Recently, as regulations on carbon emissions have been strengthened worldwide, various support policies such as subsidies for the introduction of eco-friendly vehicles instead of gasoline vehicles that emit exhaust gas have been implemented. Accordingly, the demand for electric vehicles surged, which stimulated the growth of the electric vehicle market. However, an electric vehicle using a lithium ion battery has a disadvantage in that it has a shorter mileage when charged once compared to a gasoline vehicle. Among the factors that determine the mileage of a vehicle, the energy density of the battery used occupies the largest part. Many studies have been conducted on Ni-rich lithium ion batteries to increase energy density, but to reach higher energy density, the next generation of Na-ion, Lithium-Air, Lithium-Sulfur, and all solid state batteries have been developed. Research and development of batteries is inevitable.
Among many next-generation batteries, lithium-sulfur (Li-S) batteries not only have high theoretical capacity (~1675 mAh g-1) and energy density (~2500 Wh kg-1), but also have abundant sulfur resources used as active materials, making them economical. In addition, it has the advantage of being able to increase the energy density by using Li metal having a high theoretical capacity (~3860 mAh g-1) and a low oxidation/reduction potential as a anode.
However, in Li-S batteries, carbon-based conductive materials are used together due to the low electrical conductivity of the reactant S8 (5 x 10-30 S cm-1) and the product Li₂S (1 x 10-13 S cm-1). It has several disadvantage in that the energy density is lowered due to a decrease in the ratio of the active material, and lithium polysulfide (Li₂Sx, 4≤x≤8), an intermediate product generated during the electrochemical reaction, is dissolved in a liquid electrolyte used as a lithium ion transport medium. Since the sulfide shuttle effect occurs, loss of active material and deterioration of battery performance, it is difficult to put into practical.
In this study, an oxide-based solid electrolyte and a polymer-based solid electrolyte were combined to prepare a composite solid electrolyte that complemented each other's shortcomings. In addition, by using this composite solid electrolyte instead of a liquid electrolyte, the polysulfide shuttle effect was physically suppressed. At the same time, ignited materials were removed, thereby improving the safety of the battery. In an all-solid-state lithium-sulfur battery manufactured using a composite solid electrolyte, the ratio of carbon, a conductive material added to improve the low electrical conductivity of sulfur, and sulfur, a cathode active material, affects the all-solid-state lithium-sulfur battery. Experiments were carried out for each ratio of carbon. Experiments were conducted for each ratio of sulfur and carbon to determine whether the In addition, many studies are being conducted to improve the performance degradation in high-loading due to the low conductivity of all solid state Li-S batteries, and among them, the research was conducted focusing on the current collector. A study was conducted to confirm whether 3D current collector carbon cloth used instead of the existing 2D current collector Al foil can contribute to the improvement of the performance of all solid state Li-S batteries.