Finely‐Dispersed Ni<sub>2</sub>Co Nanoalloys on Flower‐Like Graphene Microassembly Empowering a Bi‐Service Matrix for Superior Lithium–Sulfur Electrochemistry
Gaoran Li, Weilong Qiu, Wanjie Gao, Yaojie Zhu, Xiaomin Zhang, Hongyang Li, Yongguang Zhang, Xin Wang, Zhongwei Chen
Abstract
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 Ni 2 Co nanoalloy (Ni 2 Co@rGO) is developed as advanced host matrix for Li–S batteries. Combining computational, physicochemical, and electrochemical studies, Ni 2 Co 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 Ni 2 Co@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‐Ni 2 Co@rGO cathode and Li‐Ni 2 Co@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.