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通过高速喷雾热解对 Si-SiO-C 复合材料进行精细结构控制,用于锂离子电池阳极。

Delicate Structural Control of Si-SiO-C Composite via High-Speed Spray Pyrolysis for Li-Ion Battery Anodes.

机构信息

Graduate School of Energy, Environment, Water, and Sustainability (EEWS) and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST) , 291 Daehakro, Yuseong-gu, Daejeon 34141, Republic of Korea.

Department of Chemistry and Earth Sciences, College of Arts and Sciences, Qatar University , P.O. Box 2713, Doha, Qatar.

出版信息

Nano Lett. 2017 Mar 8;17(3):1870-1876. doi: 10.1021/acs.nanolett.6b05191. Epub 2017 Feb 16.

Abstract

Despite the high theoretical capacity, silicon (Si) anodes in lithium-ion batteries have difficulty in meeting the commercial standards in various aspects. In particular, the huge volume change of Si makes it very challenging to simultaneously achieve high initial Coulombic efficiency (ICE) and long-term cycle life. Herein, we report spray pyrolysis to prepare Si-SiO composite using an aqueous precursor solution containing Si nanoparticles, citric acid, and sodium hydroxide (NaOH). In the precursor solution, Si nanoparticles are etched by NaOH with the production of [SiO]. During the dynamic course of spray pyrolysis, [SiO] transforms to SiO matrix and citric acid decomposes to carbon surface layer with the assistance of NaOH that serves as a decomposition catalyst. As a result, a Si-SiO composite, in which Si nanodomains are homogeneously embedded in the SiO matrix with carbon surface layer, is generated by a one-pot process with a residence time of only 3.5 s in a flow reactor. The optimal composite structure in terms of Si domain size and Si-to-O ratio exhibited excellent electrochemical performance, such as reversible capacity of 1561.9 mAh g at 0.06C rate and ICE of 80.2% and 87.9% capacity retention after 100 cycles at 1C rate.

摘要

尽管硅(Si)理论比容量较高,但在锂离子电池中其作为负极材料仍难以满足各方面的商业标准。特别是 Si 的巨大体积变化使其在同时实现高初始库仑效率(ICE)和长循环寿命方面极具挑战性。在此,我们报告了一种使用含有 Si 纳米颗粒、柠檬酸和氢氧化钠(NaOH)的水性前体溶液通过喷雾热解制备 Si-SiO 复合材料的方法。在前体溶液中,Si 纳米颗粒会被 NaOH 刻蚀,生成 [SiO]。在喷雾热解的动态过程中,[SiO] 在 NaOH 的协助下转化为 SiO 基体,柠檬酸分解为碳表面层,NaOH 作为分解催化剂。因此,在仅 3.5 s 的停留时间内,通过一锅法在流反应器中生成 Si 纳米区均匀嵌入 SiO 基体并带有碳表面层的 Si-SiO 复合材料。在最佳的 Si 域尺寸和 Si-O 比的复合结构下,表现出优异的电化学性能,例如在 0.06C 倍率下的可逆容量为 1561.9 mAh g,在 1C 倍率下循环 100 次后的 ICE 为 80.2%和 87.9%的容量保持率。

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