Xiang Yinger, Xu Laiqiang, Yang Li, Ye Yu, Ge Zhaofei, Wu Jiae, Deng Wentao, Zou Guoqiang, Hou Hongshuai, Ji Xiaobo
College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, People's Republic of China.
College of Science, Hunan University of Technology and Business, Changsha, 410205, People's Republic of China.
Nanomicro Lett. 2022 Jun 17;14(1):136. doi: 10.1007/s40820-022-00873-x.
The chemical process of local oxidation-partial reduction-deep coupling for stibnite reduction of carbon dots (CDs) is revealed by in-situ high-temperature X-ray diffraction. SbS@xCDs anode delivers high initial coulombic efficiency in lithium ion batteries (85.2%) and sodium ion batteries (82.9%), respectively. C-S bond influenced by oxygen-rich carbon matrix can restrain the conversion of sulfur to sulfite, well confirmed by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations. CDs-induced Sb-O-C bond is proved to effectively regulate the interfacial electronic structure. The application of SbS with marvelous theoretical capacity for alkali metal-ion batteries is seriously limited by its poor electrical conductivity and low initial coulombic efficiency (ICE). In this work, natural stibnite modified by carbon dots (SbS@xCDs) is elaborately designed with high ICE. Greatly, chemical processes of local oxidation-partial reduction-deep coupling for stibnite reduction of CDs are clearly demonstrated, confirmed with in situ high-temperature X-ray diffraction. More impressively, the ICE for lithium-ion batteries (LIBs) is enhanced to 85%, through the effect of oxygen-rich carbon matrix on C-S bonds which inhibit the conversion of sulfur to sulfite, well supported by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations. Not than less, it is found that Sb-O-C bonds existed in the interface effectively promote the electronic conductivity and expedite ion transmission by reducing the bandgap and restraining the slip of the dislocation. As a result, the optimal sample delivers a tremendous reversible capacity of 660 mAh g in LIBs at a high current rate of 5 A g. This work provides a new methodology for enhancing the electrochemical energy storage performance of metal sulfides, especially for improving the ICE.
原位高温X射线衍射揭示了用于辉锑矿还原碳点（CDs）的局部氧化-部分还原-深度耦合的化学过程。SbS@xCDs阳极在锂离子电池（85.2%）和钠离子电池（82.9%）中分别具有较高的初始库仑效率。受富氧碳基体影响的C-S键可以抑制硫向亚硫酸盐的转化，这通过固体电解质界面层的X射线光电子能谱表征以及密度泛函理论计算得到了很好的证实。CDs诱导的Sb-O-C键被证明能有效调节界面电子结构。具有出色理论容量的SbS在碱金属离子电池中的应用因其低电导率和低初始库仑效率（ICE）而受到严重限制。在这项工作中，精心设计了具有高ICE的碳点修饰天然辉锑矿（SbS@xCDs）。极大地，通过原位高温X射线衍射证实，清晰展示了用于辉锑矿还原CDs的局部氧化-部分还原-深度耦合的化学过程。更令人印象深刻的是，通过富氧碳基体对C-S键的影响抑制硫向亚硫酸盐的转化，锂离子电池（LIBs）的ICE提高到了85%，固体电解质界面层的X射线光电子能谱表征以及密度泛函理论计算很好地支持了这一点。同样重要的是，发现界面处存在Sb-O-C键通过降低带隙和抑制位错滑移有效地促进了电子传导并加快了离子传输。结果，最佳样品在5 A g的高电流密度下在LIBs中提供了660 mAh g的巨大可逆容量。这项工作为提高金属硫化物的电化学储能性能，特别是提高ICE提供了一种新方法。
