Synchronous sulfurization and carbonization using sulfur-rich metal-organic frameworks for fast-charge sodium-ion batteries

• Published in: Journal of power sources 2020-12, Vol.478, p.228778, Article 228778
• Main Authors: Wu, Yanchao, Zhuo, Shuming, Tang, Mi, Chen, Yuan, Wang, Bo, Zhu, Shaolong, Fan, Kun, Jiang, Cheng, Wang, Chengliang
• Format: Article
• Language: English
• Subjects: Composites; Fast charge; Metal sulfides; Metal-organic frameworks; Sodium-ion batteries
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2020.228778

Metal sulfides are one of the most promising anode materials for sodium-ion batteries (SIBs) due to their high theoretical capacity and appropriate electrode potential. However, these materials are still suffering from the low conductivity, large volume change during the charge-discharge process, sluggish reaction kinetics and poor cycle stability. Herein, we report a new strategy to synthesize CoSx-carbon composite (CoSx@C) from a sulfur-rich metal-organic framework for SIBs. The synchronous sulfurization and carbonization facilitated the formation of homogenous composites and the small amount of carbon in the composites significantly enhanced the intrinsic conductivity. As a result, the obtained CoSx@C electrodes showed a high specific capacity of 664 mAh g−1 after 400 cycles at 0.5 A g−1. When the current density increased from 0.2 to 5 A g−1, the capacity only decreased slightly from 653 to 601 mAh g−1, with retention as high as 90%. The capacity and the rate performance outperformed most of the reported cobalt sulfide anodes for SIBs. •Synchronous sulfurization and carbonization were achieved by using sulfur-rich MOFs.•The obtained CoSx-carbon composites showed high conductivity.•The CoSx@C electrodes showed high capacity and rate capability.