What progress has been made in the research of high volume energy density lithium-sulfur batteries by Fujian Institute of Physics

　　Lithium-ion batteries are widely used in our daily lives. With the urgent demand for high-capacity energy storage devices in emerging electronic products such as portable electronic equipment and electric vehicles, traditional lithium-ion batteries are far from meeting our demand for energy storage.

　　Lithium-ion batteries are widely used in our daily lives. With the urgent demand for high-capacity energy storage devices in emerging electronic products such as portable electronic equipment and electric vehicles, traditional lithium-ion batteries are far from meeting our demand for energy storage. 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 low cost and environmental friendliness of sulfur. However, there are still some technical challenges in the commercial application of lithium-sulfur batteries, such as the insulation of sulfur and solid-state discharge products, the shuttle effect of soluble polysulfides, and changes in the volume of sulfur during charging and discharging. These problems usually lead to low sulfur utilization, poor cycle life, and even a series of safety problems. How to greatly increase the energy density of lithium-sulfur batteries while increasing their stability has become one of the current research hotspots.

　　With the support of the National Natural Science Foundation of China and the Chinese Academy of Sciences’ Strategic Leading Science and Technology Project, Ruihu Wang’s research group and Xiao Zhubing, a researcher at the State Key Laboratory of Structural Chemistry, Fujian Institute of the Structure of Matter, synthesized vanadium sulfide loaded vanadium sulfide through a simple hydrothermal reaction. The layered material of graphene oxide (rGO-VS2) was reduced, and a series of rGO-VS2/S positive electrode materials of sandwich structure formed by alternately and closely packing rGO-VS2 sheets and sulfur monolayers were prepared. The sandwich structure of rGO-VS2 sheet layer and active sulfur layer alternately can withstand the volume change of the active material during the charge and discharge cycle through the elastic contraction and 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 loaded on the graphene sheet can effectively inhibit the shuttle effect of polysulfides and promote the redox reaction of the entire sulfur element layer, thereby improving The utilization rate and cycle stability of sulfur active substances. The rGO-VS2/S loaded with 89 wt% sulfur has a high tap density of 1.84 g cm-3, and its volumetric specific capacity reaches 1182.1 mA h cm-3 under 0.1 C discharge conditions, and it can still be maintained at 1050 mA h after 100 cycles. cm-3. This study shows that the introduction of electrocatalytic components with high conductivity and strong polysulfide adsorption capacity into a stretchable sandwich structure can obtain a lithium-sulfur battery cathode material with superior performance, which is for the development of long-life, high-energy-density lithium-sulfur batteries Provides new ideas. The research results were published in "Advanced Energy Materials" in the form of a cover article, and were promoted and introduced by MaterialsViewsChina.