Finely‐Dispersed Ni2Co Nanoalloys on Flower‐Like Graphene Microassembly Empowering a Bi‐Service Matrix for Superior Lithium–Sulfur Electrochemistry

• Published in: Advanced functional materials Vol. 32; no. 32
• Main Authors: Li, Gaoran, Qiu, Weilong, Gao, Wanjie, Zhu, Yaojie, Zhang, Xiaomin, Li, Hongyang, Zhang, Yongguang, Wang, Xin, Chen, Zhongwei
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.08.2022
• Subjects: Anodes; catalyses; Catalytic activity; Catalytic converters; Conversion; Dispersion; Electrochemistry; Energy storage; Flowers; Graphene; Ion transport; Kinetics; Lithium sulfur batteries; Local current; Materials science; microassemblies; Nanoalloys; shuttle effect
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202202853

Lithium–sulfur (Li–S) batteries present a promising solution to high‐energy and low‐cost energy storage. However, the conversion‐type redox mechanism determines the poor fulfillment of battery chemistry in terms of reversibility and kinetics. Herein, a flower‐like graphene microassembly decorated with finely‐dispersed Ni2Co nanoalloy (Ni2Co@rGO) is developed as advanced host matrix for Li–S batteries. Combining computational, physicochemical, and electrochemical studies, Ni2Co nanoalloys are unveiled synergizing strong adsorbability against polysulfide shuttling and excellent catalytic activity for sulfur conversions. Meanwhile, the sophisticated architecture renders facile electron/ion transport and highly‐exposed active interfaces. These virtues collaboratively contribute to fast and durable sulfur electrochemistry with a minimum capacity degradation of 0.034% per cycle over 500 cycles and a rate capability up to 5 C. Besides, the implementation of Ni2Co@rGO as the anode matrix tames the Li redox behavior benefiting from the enhanced lithiophilicity and reduced local current density. As such, the full cell configuration pairing S‐Ni2Co@rGO cathode and Li‐Ni2Co@rGO anode realizes a favorable areal capacity of 4.53 mAh cm−2 under high sulfur loading (4.0 mg cm−2) and limited electrolyte (E/S = 6.0 mL g−1). This work offers an elaborate bi‐service matrix engineering to simultaneously improve the conversion reversibility and kinetics for superior Li–S batteries. Sophisticated flower‐like graphene microassembly decorated with finely‐dispersed N2Co nanoalloys is developed as a bi‐service electrode host matrix in lithium–sulfur batteries. The unique architecture and nanoalloy design realize reversible redox conversion electrochemistry in both sulfur and lithium electrodes, holding great potential for the development of high‐performance and practically viable Li–S batteries.