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Professor Lin Zhan's team has made important progress in the field of lithium sulfur battery research

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Recently, Professor Lin Zhan's team in the school of light industry and chemical engineering of our university has made important progress in the research field of lithium sulfur batteries. The research results entitled "integration conductivity, mobility, and catalytic ability into high-N carbon / graphene sheets as an effective sulfur host" were published in the international authoritative journal adv. mater. (if = 25.809, top journal in zone I).In this paper, Professor Lin Zhan's team proposed the importance of conductivity / in-situ anchoring / catalytic conversion of polysulfides, which provided a new idea for the construction of sulfur positive electrode for high-performance lithium-sulfur batteries.Professor Lin Zhan / Associate Professor Chen Chao of the College of light industry and chemical engineering is the corresponding author of the paper. Xu Huifang, a graduate student, is the first author of the paper. Our university is the only author of the paper.

Compared with the cathode materials for lithium-ion batteries, sulfur electrodes not only have high theoretical specific capacity (1675 MAH g-1), but also have rich resources, low price and environmental friendliness, which have attracted extensive attention in recent years.However, the poor conductivity of sulfur and its discharge product lithium sulfide (Li2S), the "shuttle effect" of soluble lithium polysulfide (LIPSS) and the volume expansion effect lead to irreversible degradation of battery capacity and low coulomb efficiency.In 2000 research papers published in the past five years (August 8, 2014 to August 8, 2019), ~ 90% of the research papers usually add lithium nitrate (LiNO3) to the electrolyte to react with the metal lithium anode, forming a solid electrolyte interface layer on the lithium surface, blocking the reaction between LIPSS diffused to the negative electrode and lithium metal, and completing the charging and discharging process.However, adding LiNO3 into electrolyte can not solve the problem of dissolution diffusion of LIPSS.In recent years, researchers have found that the addition of polar materials with catalytic ability can promote the conversion of LIPSS to Li2S. However, it is difficult for such materials to have high conductivity and good LIPSS anchoring ability.Therefore, how to design multi-functional carriers to effectively solve the above problems and achieve excellent electrochemical performance of sulfur positive electrode has become a hot research topic in the field of lithium sulfur battery.

Based on this, Professor Lin Zhan's team designed a graphene sheet (NC / g) composite material with ultra-high nitrogen content (17.1%) as sulfur cathode carrier. The experimental results and theoretical calculation show that the carrier has both large pore volume and high conductivity, and can synchronously absorb and convert LIPSS. Therefore, it overcomes many disadvantages of lithium sulfur battery, even if the electrolyte is not added with LiNO3In addition, the high load sulfur cathode can also achieve excellent cycle stability.Based on the experimental and theoretical calculation results, this paper first proposed and proved that excellent sulfur cathode carrier materials should have the following three indispensable factors: (I) high conductivity can effectively promote charge transfer to realize sulfur conversion; (II) strong binding force between the carrier and LIPSS can prevent LIPSS from dissolving in the electrolyte and slow down the shuttle effect of LIPSS;(III) abundant active sites promote the rapid conversion of LIPSS to Li2S.This work has a very important guiding significance for scientific researchers to reasonably design efficient sulfur carrier and realize the practical potential of sulfur positive electrode of lithium sulfur battery in future research.

Paper links:https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.201906357

Professor Lin Zhan's team is mainly engaged in the design, development and application basic research of new energy and catalytic new materials, including lithium-ion battery, lithium sulfur battery, new power supply, fuel cell and photochemical / electrochemical catalysis.In 2019, the team achieved a number of innovative scientific research achievements in the field of energy storage and conversion, and published 18 SCI academic papers in well-known journals at home and abroad, including 11 papers with impact factor if > 10 (NAT. Commun., adv. mater, adv. energy mater, ACS catalysis, etc.), and 2 top journals in chemical industry (chem. Eng. J.),In most of the above papers, Guangdong University of technology is the first / only communication unit.