Scientists have made breakthroughs in lithium-ion batteries, and batteries may become smaller!

　　With the increasing demand for energy storage, higher and higher requirements have been placed on the performance of secondary batteries. Nanotechnology can make batteries "lighter" and "faster", but due to the lower density of nanomaterials, "smaller" has become a problem facing researchers in the field of energy storage.

　　How can electronic consumer products such as mobile phones and notebook computers be lighter and thinner, and how can electric vehicles have a longer range of power in the limited car body space... With the increasing demand for energy storage, the performance of secondary batteries is also affected. Put forward higher and higher requirements. Nanotechnology can make batteries "lighter" and "faster", but due to the lower density of nanomaterials, "smaller" has become a problem facing researchers in the field of energy storage.

　　The research team of Professor Yang Quanhong, the winner of the National Science Fund for Distinguished Young Scholars and the Tianjin University School of Chemical Engineering, proposed the "sulfur template method". Through the design of anode materials for high-volume energy density lithium-ion batteries, the "tailor-made" coating of active particles by graphene was finally completed. Make lithium-ion batteries "smaller" possible. The results were published online on "NatureCommunicaTIons" on January 26.

　　As the most widely used secondary battery at the moment, lithium ion batteries have a very high energy density. Non-carbon materials such as tin and silicon are expected to replace the current commercial graphite as a new generation of negative electrode materials, greatly increasing the mass energy density (Whkg-1) of lithium-ion batteries, but their huge volume expansion severely limits their volume performance advantages. The carbon cage structure constructed by carbon nanomaterials is considered to be the main means to solve the huge volume expansion problem of non-carbon anode materials when intercalating lithium; The density is greatly reduced, which limits the volumetric performance of the lithium-ion battery's negative electrode. Therefore, the precise customization of the carbon cage structure is not only an important academic problem, but also the only way for the industrialization of new high-performance anode materials.

　　Professor Quanhong Yang’s research team and collaborators from Tsinghua University, the National Nano Center and the National Institute of Materials have made breakthroughs in the design of high-volume energy density lithium-ion battery anode materials. Based on graphene interface assembly, they invented the precise customization of dense porous carbon cages. Sulfur template technology. In the process of using capillary evaporation technology to build a dense graphene network, they introduced sulfur as a flowable volume template to customize the graphene carbon coat for non-carbon active particles. By modulating the amount of sulfur template used, the three-dimensional graphene carbon cage structure can be precisely adjusted to achieve a "fitting" coating of the size of non-carbon active particles, so as to effectively buffer the huge volume expansion of lithium intercalation of non-carbon active particles. The negative electrode of ion battery exhibits excellent volume performance.

　　Graph Sulfur Template Method for Accurate Design of Graphene Carbon Cage Structure

　　The sulfur template method is proposed, in the three-dimensional graphene dense network, clever use of sulfur like "transformers" like fluidity, amorphous, and easy to remove characteristics, to achieve the same effect on non-carbon active particles inside the carbon cage structure. Tight coating of tin oxide nanoparticles. Compared with the traditional "shape" template, the biggest advantage of the sulfur template is that it can play the role of a plastic volume template, so that the compact graphene cage structure can provide a conformable and accurately controllable size reserve space, and finally complete the target The "tailor-made" of active tin dioxide. This kind of carbon-non-carbon composite electrode material with suitable reserved space and maintaining high density can contribute extremely high volumetric specific capacity, thereby greatly increasing the volumetric energy density of lithium-ion batteries and making lithium-ion batteries smaller. This "tailor-made" design idea can be extended to a universal next-generation high-energy lithium-ion battery, lithium-sulfur battery, lithium-air battery and other electrode materials construction strategies.