Hierarchical Micro‐Nanoclusters of Bimetallic Layered Hydroxide Polyhedrons as Advanced Sulfur Reservoir for High‐Performance Lithium–Sulfur Batteries

• Published in: Advanced science Vol. 8; no. 7; pp. 2003400 - n/a
• Main Authors: Qiu, Weilong, Li, Gaoran, Luo, Dan, Zhang, Yongguang, Zhao, Yan, Zhou, Guofu, Shui, Lingling, Wang, Xin, Chen, Zhongwei
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 01.04.2021; John Wiley and Sons Inc; Wiley
• Subjects: Energy storage; Etching; Graphene; hollow polyhedrons; layered double hydroxides; lithium–sulfur batteries; nano‐micro hierarchies; Nitrates; Pore size; spray drying; Sulfur; Surface chemistry; layered double hydroxides; lithium–sulfur batteries; nano‐micro hierarchies; hollow polyhedrons; spray drying
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202003400

Rational construction of sulfur electrodes is essential in pursuit of practically viable lithium–sulfur (Li–S) batteries. Herein, bimetallic NiCo‐layered double hydroxide (NiCo‐LDH) with a unique hierarchical micro‐nano architecture is developed as an advanced sulfur reservoir for Li–S batteries. Compared with the monometallic Co‐layered double hydroxide (Co‐LDH) counterpart, the bimetallic configuration realizes much enriched, miniaturized, and vertically aligned LDH nanosheets assembled in hollow polyhedral nanoarchitecture, which geometrically benefits the interface exposure for host–guest interactions. Beyond that, the introduction of secondary metal intensifies the chemical interactions between layered double hydroxide (LDH) and sulfur species, which implements strong sulfur immobilization and catalyzation for rapid and durable sulfur electrochemistry. Furthermore, the favorable NiCo‐LDH is architecturally upgraded into closely packed micro‐nano clusters with facilitated long‐range electron/ion conduction and robust structural integrity. Due to these attributes, the corresponding Li–S cells realize excellent cyclability over 800 cycles with a minimum capacity fading of 0.04% per cycle and good rate capability up to 2 C. Moreover, highly reversible areal capacity of 4.3 mAh cm−2 can be achieved under a raised sulfur loading of 5.5 mg cm−2. This work provides not only an effective architectural design but also a deepened understanding on bimetallic LDH sulfur reservoir for high‐performance Li–S batteries. A unique NiCo‐LDH@rGO micro‐nano hierarchical composite is developed as a synergistic sulfur immobilizer and promoter to realize high‐efficiency lithium–sulfur battery chemistry. The unique architecture of NiCo‐LDH@rGO and its strong chemical interactions with the intermediate polysulfides afford large space for sulfur, enable expedite ion/mass transfer, and effectively restrain and catalyze the conversion of polysulfide.