Implantation of Fe7S8 nanocrystals into hollow carbon nanospheres for efficient potassium storage

Yifan Xu; Jianbo Li; Jianlu Sun; Liping Duan; Jianzhi Xu; Dongmei Sun; Xiaosi Zhou

doi:10.1016/j.jcis.2022.02.041

Implantation of Fe₇S₈ nanocrystals into hollow carbon nanospheres for efficient potassium storage

J Colloid Interface Sci. 2022 Jun:615:840-848. doi: 10.1016/j.jcis.2022.02.041. Epub 2022 Feb 12.

Authors

Yifan Xu¹, Jianbo Li¹, Jianlu Sun¹, Liping Duan¹, Jianzhi Xu¹, Dongmei Sun², Xiaosi Zhou³

Affiliations

¹ Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China.
² Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China. Electronic address: sundongmei@njnu.edu.cn.
³ Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China. Electronic address: zhouxiaosi@njnu.edu.cn.

PMID: 35182854
DOI: 10.1016/j.jcis.2022.02.041

Abstract

As a desirable candidate for lithium-ion batteries, potassium-ion batteries (PIBs) have aroused great interest because of their low cost and high power and energy densities. However, the insertion/extraction of K⁺ with a large radius (1.38 Å) usually bring about the destruction of the electrode materials. Here, ultrafine Fe₇S₈ nanocrystals are successfully implanted into hollow carbon nanospheres (Fe₇S₈@HCSs) via a facile solvothermal method and subsequent novel low-temperature sulfurization, which avoid the aggregation of Fe₇S₈ nanoparticles produced during high-temperature sulfidation. The ultrafine Fe₇S₈ nanoparticles and hollow carbon spheres can not only buffer the severe expansion/shrinkage of electrode materials caused by the repeated insertion/extraction of K⁺, but also provide additional accessible pathways for the high-rate K⁺ transmission. When tested as an anode material for PIBs, Fe₇S₈@HCSs achieve impressive K⁺ storage capacity of 523.2 mAh g^-1 at 0.1 A g^-1 after 100 cycles and remarkable rate capacity of 176.3 mAh g^-1 at 5 A g^-1. Further, assembling this anode with a K₂NiFe(CN)₆ cathode yields stable cycling performance, revealing its great potential for large-scale energy storage applications.

Keywords: Anode; Carbon nanospheres; Hollow structure; Iron sulfide; Potassium-ion batteries.