Enhanced sulfur utilization in lithium-sulfur batteries by hybrid modified separators. (March 2021)

• Record Type: Journal Article
• Authors: Zhou, Lei; Li, Hao; Zhang, Yue; Jiang, Ming; Danilov, Dmitri L.; Eichel, Rüdiger-A.; Notten, Peter H.L.
• Is Part Of: Materials today communications. Volume 26(2021)
• Publication Date: 2021-03
• Subjects: Li-S battery -- Polysulfide -- Carbon nanotube -- Layered double hydroxide -- Chemical bonding; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2021.102133
• Languages: English
• ISSNs: 2352-4928

Abstract

Graphical abstract: An Mn-Fe LDH and carbon nanotubes hybrid modified separator has been proven to significantly inhibit the shuttle issue of polysulfides and accelerate their redox reaction kinetics, achieving enhanced sulfur utilization for Li-S batteries. Highlights: MFLC-modified separators significantly boost sulfur utilization of Li-S batteries. Li-S batteries with MFCL separators show excellent capacity and cycling stability. Polysulfide confinement and redox kinetics can be evaluated by discharge plateaus. Abstract: The extraordinary energy density and low cost enable lithium-sulfur (Li-S) batteries to be a promising alternative to traditional energy storage systems. The principal hurdle facing Li-S batteries is the unsatisfactory utilization of sulfur cathodes. The detrimental shuttle issue of polysulfides and the sluggish charge transfer kinetics result in quick capacity degradation of Li-S batteries. An MFLC hybrid material composed of manganese-iron layered double hydroxides (Mn-Fe LDH) and carbon nanotubes (CNT) has been developed. Such heterostructure combines the advantages of effective chemical bonding of Mn-Fe LDH towards polysulfides with the high conductivity of CNT. When modified on a polypropylene (PP) separator, the hybrid material is proven to significantly inhibit the shuttle issue of polysulfides and accelerate their redox reaction kinetics. Li-S batteries with MFLC-modified separators revealed considerably improved electrochemical performance. A high initial capacity of 1138 mA h g −1 and 70 % capacity retention after 200 cycles were achieved at 0.2 C. The enhanced sulfur utilization can be directly evaluated from the discharge voltage plateaus. The results indicate a new solution for the practical application of Li-S batteries and provide a simple approach to determine the efficiency of sulfur utilization.