Lamellar MXene Composite Aerogels with Sandwiched Carbon Nanotubes Enable Stable Lithium–Sulfur Batteries with a High Sulfur Loading

• Published in: Advanced functional materials 2021-06, Vol.31 (26), p.n/a
• Main Authors: Zhang, Bin, Luo, Chong, Zhou, Guangmin, Pan, Zheng‐Ze, Ma, Jiabin, Nishihara, Hirotomo, He, Yan‐Bing, Kang, Feiyu, Lv, Wei, Yang, Quan‐Hong
• Format: Article
• Language: English
• Subjects: Aerogels; Barriers; Carbon nanotubes; Catalytic activity; Cycles; Decay rate; high sulfur loading; Lamellar structure; Lithium; Lithium sulfur batteries; Materials science; MXene composite aerogels; MXenes; sandwich structure; Stability; Sulfur; unidirectional freeze‐drying
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202100793

Realizing long cycling stability under a high sulfur loading is an essential requirement for the practical use of lithium–sulfur (Li–S) batteries. Here, a lamellar aerogel composed of Ti3C2Tx MXene/carbon nanotube (CNT) sandwiches is prepared by unidirectional freeze‐drying to boost the cycling stability of high sulfur loading batteries. The produced materials are denoted parallel‐aligned MXene/CNT (PA‐MXene/CNT) due to the unique parallel‐aligned structure. The lamellae of MXene/CNT/MXene sandwich form multiple physical barriers, coupled with chemical trapping and catalytic activity of MXenes, effectively suppressing lithium polysulfide (LiPS) shuttling under high sulfur loading, and more importantly, substantially improving the LiPS confinement ability of 3D hosts free of micro‐ and mesopores. The assembled Li–S battery delivers a high capacity of 712 mAh g−1 with a sulfur loading of 7 mg cm−2, and a superior cycling stability with 0.025% capacity decay per cycle over 800 cycles at 0.5 C. Even with sulfur loading of 10 mg cm−2, a high areal capacity of above 6 mAh cm−2 is obtained after 300 cycles. This work presents a typical example for the rational design of a high sulfur loading host, which is critical for the practical use of Li–S batteries A lamellar MXene/carbon nanotube (CNT) composite aerogel composed of interconnected and parallel‐aligned MXene/CNT/MXene sandwiches is prepared by a unidirectional freeze‐drying method. The lamellae of MXene/CNT/MXene sandwiches form multiple physical barriers, coupled with chemical trapping and catalytic activity of the MXenes, effectively suppressing lithium polysulfide shuttling even for the high sulfur loading lithium–sulfur batteries.