A new breakthrough in domestic lithium-sulfur battery research technology!

In 2020, it will be a hurdle for all new energy vehicles and power battery companies selling in the Chinese market. According to the "Technology Roadmap for Energy Saving and New Energy Vehicles" issued by the Ministry of Industry and Information Technology, in 2020, the energy density of pure electric vehicle power battery cells should reach 300Wh/kg, and strive to achieve 350Wh/kg, while the current mainstream lithium battery material system, The energy density will be close to the theoretical value in the next one to two years, and it is difficult to exceed 350Wh/kg. To manufacture batteries with higher energy density, it is necessary to develop a new battery system. Some insiders believe that the lithium-sulfur battery system is expected to become one of the high-energy density mainstream battery material systems in the future.

Recently, the team of Professor Lai Yanqing from Central South University has made a major breakthrough in the research on the high safety, long life and high specific energy of lithium-sulfur batteries, and has made breakthroughs in S-C composite construction, cyclic attenuation mechanism and sulfur-cutting lithium-lead method. A series of innovative results, related research results in NanoEnergy, EnergyStorageMaterials and J. Mater. Chem, a related energy materials published in the Top Journal. As the project leader, Professor Lai Yanqing also applied for the approval of the 2018 National Key R&D Program. It is expected that within 3 years, the project will be the first in the world to achieve high-energy (more than twice the current battery) engineering of lithium-sulfur batteries demonstration of manufacturing and loading applications.

Lithium-sulfur battery is a kind of lithium battery with sulfur element as the positive electrode of the battery and lithium metal as the negative electrode. Its theoretical specific energy is as high as 2600Wh/kg, which is much higher than the current commercial lithium-ion battery. In recent years, lithium-sulfur batteries have become one of the main research directions of high-energy new batteries due to their high energy density, theoretical capacity, abundant elemental sulfur resources, low price and environmental friendliness.

Although the technical route is relatively clear, the commercialization process of lithium-sulfur batteries faces great challenges: due to poor conductivity of the sulfur cathode material and its discharge product lithium sulfide, volumetric effects during charging and discharging, and "shuttle effect", etc. The utilization rate of sulfur in the battery is low, the capacity is attenuated quickly, and the rate performance is poor.

In response to the above problems, Professor Xu Maowen from the Department of Materials and Energy, Southwest University, designed and synthesized a double-core core-shell NiO-NiCo2O4 heterojunction C hollow nanocage as a carrier of sulfur, and was first applied to lithium-sulfur batteries. This hollow structure not only provides sufficient space for sulfur storage, but also effectively copes with the volume effect during sulfur charging and discharging. In addition, the NiO-NiCo2O4 heterojunction nanocage can utilize the unique advantages of its own composition to effectively inhibit the dissolution and diffusion of polysulfide and alleviate the shuttle effect of the battery based on this unique design, the material acts as the positive electrode of a lithium-sulfur battery and exhibits high specific capacity and good cycle stability. Battery China Network was informed that the research results were completed by Xu Maowen team and Dr. Chen Yuming of the Massachusetts Institute of Technology in the United States, and published in the top-level international energy journal "Advanced Energy Materials" under the title "Double-Shelled NiO-NiCo2O4HeterostructureCarbonHollowNanocagesasAnEfficientSulfurHostforAdvancedLithium-SulfurBatteries" (Advanced Energy Materials) )on.

Not only scientific research institutions, but also battery companies have been actively seeking technological breakthroughs in recent years, hoping to realize the commercialization of lithium-sulfur batteries as soon as possible. Considering that high-altitude drones are particularly sensitive to weight, the biggest advantage of lithium-sulfur batteries is that they have high energy density and light weight. Many enterprises at home and abroad have successively carried out lithium-sulfur battery application tests on drones.

In 2010, SIONPOWER in foreign countries applied lithium-sulfur batteries to large unmanned aerial vehicles to set a world record of three flying UAVs with the highest flying height the longest air time and the lowest operating temperature, at present, lithium-ion batteries cannot realize the long-term stagnation of drones in high-altitude low-temperature environments. Domestically, lion technology has cooperated with IMRE, a professional research institute in Singapore. Currently, samples of lithium-sulfur batteries have also been applied to drones.

At present, the industrialization research and development of lithium-sulfur batteries is still in its infancy. In addition to the need to further improve the specific capacity and stability of battery cathode materials, key issues such as battery safety are also urgently needed to be resolved. Although there are still many problems in the industrialization of lithium-sulfur batteries, in the view of Dr. Miao Lixiao, general manager of Thornton New Energy Research and Development Department, this is the best opportunity for China's new energy companies to seize the opportunity to obtain the right to speak the future lithium-sulfur batteries. During the period, power battery companies should increase investment in research and development, accelerate the breakthrough and overcome the technical difficulties of lithium-sulfur batteries, to avoid the future occupation of lithium-sulfur battery core technology, affecting the healthy development of the domestic lithium battery industry.

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