Colloidal dispersion of Nb₂O₅/reducedgraphene oxide nanocomposites as functional coating layer for polysulfideshuttle suppression and lithium anode protection of Li-S battery

Journal of Colloid and Interface Science, 2020, 566: 11-20.

QingyanMa, Mengfei Hu, Yuan Yuan, Yankai Pan, Mingqi Chen, Yayun Zhang*, Donghui Long*

文章链接：https://www.sciencedirect.com/science/article/pii/S0021979720300825

Functional separator, which bridges anode,electrolyte and cathode together, has the potential to offer a good solutionfor efficient polysulfide diffusion inhibition and anode protection of Li-Sbattery. Herein, a novel ultra-thin multifunctional separator is prepared by afacile coating of colloidal dispersion of Nb₂O₅/reduced graphene oxide nanocomposites (rGO) onto porouspolypropylene (PP) matrix. Benefiting from the physical blocking effect of rGOlayer and chemisorption of Nb₂O₅, the shuttle of polysulfides has been greatly suppressed.Meanwhile, the rGO layer functioning as a conductive upper current collectorcan improve the sulfur utilization, while the Nb₂O₅ with high activity promotes the transformation ofsulfur-containing species. With the assistant of Nb₂O₅-rGO function layer, the sulfur cathodeshows significantly improved electrochemical performance with a high specificcapacity of 1328 mAh g⁻¹ at 0.2C and754 mAh g⁻¹ retained after 200cycles. The sulfur cathode also exhibits excellent rate capability and stableCoulombic efficiency of 91% without the addition of LiNO₃ in the electrolyte. Moreover, the presence of thin Nb₂O₅-rGO layer also prevents the lithiumsurface corrosion and the dendrite growth in the lithium anode.