Sulfur template technology can make lithium batteries "slimmer"
, how electronic consumer goods such as notebook computers are lighter and thinner, how electric vehicles can have longer battery life in the limited body space... With the increasing demand for energy storage, people also put forward higher and higher requirements for the performance of secondary batteries. Nanotechnology can make batteries "lighter" and "faster", but due to the low density of nano materials, "smaller" has become a difficult problem for researchers in the field of energy storage. Professor yangquanhong, the winner of National Science Fund for Distinguished Young Scholars and the research team of Tianjin University School of chemical engineering, proposed the "sulfur template method". Through the design of cathode materials for high volume energy density lithium-ion batteries, the "tailor-made" of graphene wrapping active particles was finally completed, making it possible for lithium-ion batteries to become "smaller". This achievement was published in nature communications (September 402, 2018) on January 26
as the most widely used secondary battery at present, lithium-ion battery has high energy density. Tin, silicon and other non-carbon materials are expected to replace the current commercial graphite as a new generation of cathode materials, and greatly improve the mass energy density (WH kg-1) of lithium-ion batteries, but its huge volume expansion seriously limits its volume performance advantages. The carbon cage structure constructed by carbon nano materials is considered to be the main means to solve the problem of huge volume expansion when lithium is embedded in non carbon anode materials; However, in the construction process of carbon buffer complex, too much reserved space is often introduced, resulting in a significant reduction in the density of electrode materials, which limits the performance of lithium-ion battery cathode volume. Therefore, the precise customization of carbon cage structure is not only an important academic problem, but also the only way for the industrialization of new high-performance cathode materials
Professor Yang Quanhong's research team, together with the collaborators of Tsinghua University, the National Nanotechnology center and the National Institute of materials in Japan, made a breakthrough in the design of anode materials for high volume energy density lithium-ion batteries. Based on the graphene interface assembly, he invented the sulfur template technology accurately customized for dense porous carbon cages. In the process of constructing dense graphene complex by capillary evaporation technology, they introduced sulfur as a flowable volume template to complete the customization of graphene carbon coating for non carbon active particles. By modulating the amount of sulfur template used, the three-dimensional graphene carbon cage structure can be accurately adjusted and controlled to realize the "fit" coating of the size of non carbon active particles. Therefore, on the basis of effectively buffering the huge volume expansion of lithium embedded in non carbon active particles, it shows excellent volume performance as the cathode of lithium-ion batteries
the sulfur template method is proposed to realize the close coating of non carbon active particles such as tin dioxide nanoparticles in the carbon cage structure by skillfully using the fluidity, amorphous and easy removal of sulfur like "Transformers" in the dense complex of three-dimensional graphene. Compared with the traditional "shape" template, the biggest advantage of sulfur template is that it can play the role of plastic volume template, so that the compact graphene cage structure can provide a conformal and precisely controllable reserved space, and finally complete the "tailor-made" for active tin dioxide. This kind of carbon non carbon composite electrode material with appropriate reserved space and high density can contribute a very high volume specific capacity, thus greatly improving the volume energy density of lithium-ion batteries and making lithium-ion batteries smaller. This "tailored" design idea can be extended to the construction strategy of the next generation of universal high-energy lithium-ion batteries, lithium sulfur batteries, lithium air batteries and other electrode materials
Professor Yang Quanhong's research team has made a series of important progress in the field of compact energy storage that emphasizes the volume performance of devices in recent years. It has invented the strategy of capillary evaporation of graphene gel, which undoubtedly densifies carbon materials. It has solved the bottleneck problem of the weak decline in the spot market of steel raw materials on December 10 and the "fish and bear's paw" porosity, and obtained materials with abnormal positions of high-density porous carbon pendulum; Pursuing the small volume and high capacity of energy storage devices, this paper puts forward the design principles of high volume energy density energy storage devices from five aspects: strategies, methods, materials, electrodes and devices, and finally realizes the construction of high volume and capacity energy storage materials, electrodes and devices from supercapacitors, sodium ion capacitors, lithium sulfur batteries, lithium air batteries to lithium ion batteries, It laid the foundation for the practicality of carbon nano materials, gradually eliminated the varieties with high quality and safety risks, and effectively promoted the practical process of new electrochemical energy storage devices based on carbon nano materials. Relevant work was published in scientific reports (2013, 3, 2795), Energy Environmental Science (2015, 8, 1390), energy storage materials (2015, 1, 112), advanced materials (2015, 27, 8082), Energy Environmental Science (2016, 9, 3135), small (2017, 13,), energy storage materials (2017, 9, 134) 《Advanced Energy Materials》（DOI: 10. 1002/aenm.）、 《Advanced Energy Materials》（DOI: 10.1002/aenm.） And so on