材料科学
阳极
退火(玻璃)
空隙(复合材料)
化学工程
兴奋剂
电化学
离子
纳米技术
电极
化学
物理化学
复合材料
光电子学
工程类
有机化学
作者
Xiangtao Yu,Xiangyu Ren,Zhangfu Yuan,Xinmei Hou,Tao Yang,Mingyong Wang
标识
DOI:10.1002/advs.202205556
摘要
Iron group metals chalcogenides, especially NiS, are promising candidates for K-ion battery anodes due to their high theoretical specific capacity and abundant reserves. However, the practical application of NiS-based anodes is hindered by slow electrochemical kinetics and unstable structure. Herein, a novel structure of Ni3 S2 -Ni hybrid nanosphere with intra-core voids encapsulated by N-doped carbon shells (Ni3 S2 -Ni@NC-AE) is constructed, based on the first electrodeposited NiS nanosphere particles, dopamine coating outer layer, oxygen-free annealing treatment to form Ni3 S2 -Ni core and N-doped carbon shell, and selective etching of the Ni phase to form intra-core void. The electron/K+ transport and K+ storage reaction kinetics are enhanced due to shortened diffusion pathways, increased active sites, generation of built-in electric field, high K+ adsorption energies, and large electronic density of states at Fermi energy level, resulting from the multi-structures synergistic effect of Ni3 S2 -Ni@NC-AE. Simultaneously, the volume expansion is alleviated due to the sufficient buffer space and strong chemical bonding provided by intra-core void and yolk-shell structure. Consequently, the Ni3 S2 -Ni@NC-AE exhibits excellent specific capacity (438 mAh g-1 at 0.1 A g-1 up to 150 cycles), outstanding rate performances, and ultra-stable long-cycle performance (176.4 mAh g-1 at 1 A g-1 up to 5000 cycles) for K-ion storage.
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