What progress has been made in the study of high-volume energy density lithium-sulfur batteries in Fujian Institute of physical structure

Lithium-ion batteries are widely used in our daily life. Conventional lithium-ion batteries are far from meeting our energy storage needs with the urgent need for high-capacity energy storage devices for new electronic devices such as portable electronic devices and electric vehicles. Lithium-sulfur batteries are regarded as one of the most promising high-capacity storage systems due to their high theoretical specific capacity and energy density, as well as the advantages of low cost and environmental friendliness of sulfur. However, some technical challenges remain in the commercialization of lithium sulphur batteries, such as the insulation of sulfur and solid-state discharge products, the shuttle effect of soluble polymetallic sulphides, and the change in sulfur volume during charging and discharging. These problems usually lead to low sulfur utilization, poor cyclic life, and even a series of safety problems. How to increase the energy density of lithium-sulfur battery and increase its stability has become one of the hot topics of research.

Under the support of the National Natural Science Foundation and the Chinese Academy of Sciences 'strategic leading science and technology project, Wangruihu, a researcher of the State Key Laboratory of Structural Chemistry at the Fujian Institute of Material Structure of the Chinese Academy of Sciences, synthesized the reduced graphene oxide(rGO-VS2) layered materials loaded with vanadium sulfide through simple water-thermal reactions. A series of sandwich structure rGO-VS2/S positive electrode materials formed by alternating close accumulation of rGO-VS2 layer and sulfur elemental layer were prepared. The sandwich structure formed by alternating the rGO-VS2 layer with the active sulfur layer can withstand the volume changes of the active material during the charging and discharging cycle through the elastic contraction expansion in the three-dimensional direction.

At the same time, due to the high polarity, conductivity, and electrocatalytic activity of vanadium sulfide, a small amount of vanadium sulfide load on graphene tablets can effectively inhibit the shuttle effect of polymetallic sulphides and promote the Redox reaction of the entire sulfur monoplasmic layer. In order to improve the utilization rate and cyclic stability of sulfur active substances. The rGO-VS2/S loaded with 89 Wt % sulfur has a high-vibration solid density of 1.84 g cm-3, and its volume-to-capacity ratio reaches 1182.1 mA H cm-3 under 0.1 C discharge conditions. The cycle of 100 laps can still be maintained at 1050 mA H cm-3. The study shows that the electrocatalytic components with high conductivity and strong adsorption capacity of polysulfides in retractable sandwich structures can obtain positive electrode materials with superior properties, which provides a new idea for the development of long-lived and high-energy density lithium sulfides. The results of the study were published on the cover article "Advanced Energy Materials" and were promoted by MaterialsViewsChina.

The page contains the contents of the machine translation.