Surface-Modified Tin Nanoparticles and Their Electrochemical Performance in Lithium Ion Battery Cells
Surface-Modified Tin Nanoparticles and Their Electrochemical Performance in Lithium Ion Battery Cells
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DOI：
10.1021/acsanm.9b00544
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发表时间：
2019-06-01
影响因子：
5.9
通讯作者：
Placke, Tobias
中科院分区：
文献类型：
--
作者：
Riedel, Olga;Duettmann, Anke;Placke, Tobias
由于其相对较高的可用性、低成本、高体积衰减能力和高电子导电性，锡（Sn）经常被认为是锂离子电池（lib）的阳极材料，以取代最先进的石墨碳或作为阳极复合材料的一部分。然而，由于锂化/衰减时体积变化较大，锡材料的容量保留率较低。特别是锡粒子的表面化学性质对电化学性能的影响，目前还不清楚。在这项工作中，我们全面研究了氢氧化物-(OH-)、聚乙烯吡咯烷酮-(PVP)、硫化物-(Sx-)和巯基丙酸（MPA）覆盖的两种不同粒径分布（约20 nm和约20-200 nm）的核/壳Sn/SnOx纳米粒子的合成和表征，以及不同表面修饰和尺寸对其作为锂离子电池负极电化学性能的影响。对锡纳米材料的颗粒和表面特性，即粒径、表面形貌、结晶度、热稳定性和表面化学进行了全面的研究。此外，还深入研究了这些不同配体结合粒径效应对整体电化学性能的影响。小尺寸氢氧根修饰的锡纳米粒子在循环稳定性、速率性能和减少不可逆副反应方面表现出最突出的性能。根据热重分析和电化学结果，我们认为OH-修饰不仅改善了颗粒粘结剂的相互作用，而且表现出薄的表面层，导致有效的固体电解质界面（SEI）形成。总的来说，我们可以发现不同配体之间的显著差异，从而为如何设计薄而有效的表面涂层以提高锡复合阳极的电化学性能提供了合适的策略。
Due to its relatively high availability, low cost, high volumetric delithiation capacity, and high electronic conductivity, tin (Sn) is frequently considered as anode material for lithium ion batteries (LIBs) to replace state-of-the-art graphitic carbons or to be part of anode composites. However, Sn materials suffer from their low capacity retention due to the large volume changes upon lithiation/delithiation. In particular, the influence of the surface chemistry of Sn particles on the electrochemical performance is not well understood so far. In this work, we present a comprehensive study on the synthesis and characterization of hydroxide-(OH-), polyvinylpyrrolidone- (PVP), sulfide- (Sx-), and mercaptopropionic acid (MPA)-capped core/shell Sn/SnOx nanoparticles with two different particle size distributions (approximate to 20 nm and approximate to 20-200 nm) and the influence of the different surface modifications and sizes on their electrochemical performance as negative electrodes for LIBs. The Sn nanomaterials are comprehensively studied in terms of particle and surface characteristics, i.e., their particle size, surface morphology, crystallinity, thermal stability, and surface chemistry. Further, the influence of these different ligands in combination with the particle size effect on the overall electrochemical performance is thoroughly studied. Small-sized OH--modified Sn nanoparticles show the most outstanding performance in terms of cycling stability, rate performance, and reduced irreversible side reactions. We suggest that the OH--modification improves not only the particle binder interactions but also exhibits a thin surface layer, resulting in an effective solid electrolyte interphase (SEI) formation, as indicated by thermogravimetric analysis and electrochemical results. Overall, we can show significant differences between the different ligands, thus providing a suitable strategy on how to design thin and effective surface coatings for improved electrochemical performance of Sn composite anodes.