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

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Abstract
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.
Funding Information
  • National Natural Science Foundation of China (22109072)
  • Natural Science Foundation of Jiangsu Province (BK20210349)
  • China Postdoctoral Science Foundation (2021M691586)
  • Guangdong Provincial Department of Science and Technology (2020B0909030004, 2019JC01L203)

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