A Multifunctional Separator Enables Safe and Durable Lithium/Magnesium–Sulfur Batteries under Elevated Temperature

• Published in: Advanced energy materials 2020-02, Vol.10 (5), p.n/a
• Main Authors: Zhou, Zhenfang, Chen, Bingbing, Fang, Tingting, Li, Yue, Zhou, Zhongfu, Wang, Qingjie, Zhang, Jiujun, Zhao, Yufeng
• Format: Article
• Language: English
• Subjects: Anchoring; chemical interaction; Decay rate; Dimensional stability; Electrolytes; Energy storage; Flammability; functional separators; Graphene; high safety; High temperature; high temperature performance; Lanthanum; Lithium; Lithium sulfur batteries; Magnesium; Nanowires; Organic chemistry; Polyethylene oxide; Polysulfides; Rechargeable batteries; Separators; Storage systems; Sulfur; Wettability; Zirconium oxides
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201902023

Rechargeable metal–sulfur batteries encounter severe safety hazards and fast capacity decay, caused by the flammable and shrinkable separator and unwanted polysulfide dissolution under elevated temperatures. Herein, a multifunctional Janus separator is designed by integrating temperature endurable electrospinning polyimide nonwovens with a copper nanowire‐graphene nanosheet functional layer and a rigid lithium lanthanum zirconium oxide‐polyethylene oxide matrix. Such architecture offers multifold advantages: i) intrinsically high dimensional stability and flame‐retardant capability, ii) excellent electrolyte wettability and effective metal dendritic growth inhibition, and iii) powerful physical blockage/chemical anchoring capability for the shuttled polysulfides. As a consequence, the as constructed lithium–sulfur battery using a pure sulfur cathode displays an outstandingly high discharge capacity of 1402.1 mAh g−1 and a record high cycling stability (approximately average 0.24% capacity decay per cycle within 300 cycles) at 80 °C, outperforming the state‐of‐the‐art results in the literature. Promisingly, a high sulfur mass loading of ≈3.0 mg cm−2 and a record low electrolyte/sulfur ratio of 6.0 are achieved. This functional separator also performs well for a high temperature magnesium–sulfur battery. This work demonstrates a new concept for high performance metal–sulfur battery design and promises safe and durable operation of the next generation energy storage systems. A new design of a multifunctional Janus separator by integrating temperature endurable electrospinning polyimide nonwovens, a highly reactive copper nanowires‐graphene nanosheets layer, and a rigid lithium lanthanum zirconium oxide‐polyethylene oxide matrix is designed for high capability, long cycle life, and safe, metal–sulfur batteries.