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High-performance CoSbS-based Na-ion battery anodes
Materials Today Energy ( IF 9.0 ) Pub Date : 2020-07-07 , DOI: 10.1016/j.mtener.2020.100470
Y.-H. Jang , C.-M. Park

CoSbS and its hard carbon-containing nanocomposite (CoSbS@hard-C) are prepared via simple solid-state reactions, and their potential as Na-ion battery (NIB) anode materials is investigated. The electrochemical phase change mechanism of CoSbS during Na insertion/extraction is thoroughly investigated using various ex situ analytical tools. During Na insertion, the CoSbS undergoes a topotactic transformation owing to the formation of a NaxCoSbS (x ≤ 1.6), and then, it is converted into Na3Sb, Na2S, and Co in the fully Na-inserted state via a conversion reaction. Conversely, during Na extraction, Na3Sb transforms to Sb, which alloys with Co to form CoSb. In the fully Na-extracted state, CoSb and S from Na2S are recombined into CoSbS. Owing to the interesting reaction mechanism of CoSbS, the electrochemical performance of the CoSbS and CoSbS@hard-C anodes is excellent. Specifically, when CoSbS is used as a NIB anode, the topotactic transformation between CoSbS and NaxCoSbS (x ≤ 1.6) leads to stable cycling behavior of the NIB and a volumetric capacity of ~480 mAh cm−3 is retained after 100 cycles. Additionally, the NIB with the CoSbS@hard-C anode presents highly reversible and stable capacity (~570 mAh cm−3 after 150 cycles) and fast rate capability (~500 and ~450 mAh cm−3 at 2C and 5C, respectively), which can be attributed to the presence of uniformly dispersed small (5–8 nm) CoSbS nanocrystallites in the hard carbon matrix. Therefore, CoSbS can be utilized as a new anode material for high-performance NIBs.



中文翻译:

高性能基于CoSbS的Na离子电池阳极

通过简单的固相反应制备了CoSbS及其含硬碳纳米复合材料(CoSbS @ hard-C),并研究了其作为Na离子电池(NIB)负极材料的潜力。使用各种非原位分析工具彻底研究了CoSbS在Na插入/萃取过程中的电化学相变机理。在Na插入时,CoSbS经历由于中的Na的形成的局部规整变换X CoSbS(X ≤1.6),然后,将其转换成Na 3锑,钠2通过S和Co在完全的Na-插入状态转化反应。相反,在Na提取过程中,Na 3Sb转变为Sb,然后与Co合金化形成CoSb。在完全提取Na的状态下,来自Na 2 S的CoSb和S重新结合为CoSbS。由于CoSbS有趣的反应机理,CoSbS和CoSbS @ hard-C阳极的电化学性能非常好。具体地,当CoSbS用作NIB阳极,CoSbS和Na之间的局部规整变换X CoSbS(X ≤1.6)通向NIB的稳定的循环行为和〜480毫安cm的体积容量-3是100次循环后保留。此外,带有CoSbS @ hard-C阳极的NIB具有高度可逆和稳定的容量(150次循环后约570 mAh cm -3)和快速速率能力(约500和约450 mAh cm -3)分别位于2C和5C),这可以归因于硬碳基质中均匀分散的小(5-8 nm)CoSbS纳米微晶的存在。因此,CoSbS可以用作高性能NIB的新阳极材料。

更新日期:2020-07-07
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