A trifunctional modified separator based on Fe tetraaminophthalocyanine@rGO for lithium-sulfur batteries

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2021-02, Vol.405, p.126947, Article 126947
• Main Authors: Li, Xuting, Yang, Xiaoxia, Ye, Jiajia, Xia, Guang, Fu, Zhanghua, Hu, Cheng
• Format: Article
• Language: English
• Subjects: Catalysis; Fe tetraaminophthalocyanines; Lithium anode protection; Lithium dendrite suppression; Lithium transference number
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2020.126947

[Display omitted] •FeTaPc@rGO enables a tri-functional modified separator for Li-S batteries.•The modified separator provides polysulfide permselectivity.•The modified separator enables catalyzed cathode sulfur redox.•The modified separator suppresses dendrite formations on the Li anode.•High specific capacities and stable cycling were achieved on high-loading cells. This study demonstrates a trifunctional cathode-side modified separator for lithium-sulfur (Li-S) batteries that is developed from a self-assembled composite of Fe tetraaminophthalocyanine physically adsorbed on reduced graphene oxides (FeTaPc@rGO). The modified separator provides effective trapping of lithium polysulfides (LiPSs), catalyzed sulfur redox, as well as suppressed formation of Li dendrites in one configuration. The highly catalytic and dual sulfiphilic/lithiophilic FeTaPc exhibits a tight adsorption geometry with LiPSs, which enables promoted electron exchange between the adsorbed LiPSs and the current collecting rGO. Dendrite suppression on the Li anode is enabled by the high Li-ion transference number resulted from the interactions of FeTaPc@rGO with Li-ion and its counterions. The hindering of LiPSs migrations by FeTaPc@rGO also alleviates the surface corrosion of the Li anode. The synergistic effect of the modified separator results in elevated sulfur redox kinetics, improved sulfur utilizations and stable charge/discharge cycling with areal sulfur loadings up to 5 mg cm−2 on carbon-based cathodes with high sulfur contents. This study extends the effects of modified separators to the Li anodes, opening up new opportunities for future developments of Li-S batteries.