回收矽晶粒子製備負極材料應用於鋰離子電池之研究

Silicon Anode Materials from Silicon Slicing Slurry for Lithium Ion Cells

周哲宇(Che-Yu Chou)

指導教授 ： 顏溪成

國立臺灣大學/工學院/化學工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201603519

摘要

本論文主旨開發以回收矽晶粒子製備碳矽複合材料作為鋰離子負極材料可行性之研究。在以往的研究以導電石墨導入奈米碳/矽之複合材料解決在循環過程中的體積效應與矽基材低導電的缺點。有別於奈米矽基材，本研究中利用從矽晶切削液回收之微米級矽晶粒子作為矽基材並與碳形成碳/矽複合材料。首先回收純化後的矽晶粒子與無水檸檬酸進行不同比列混合而形成碳矽複合材料。在電池循環測試中，無水檸檬酸與回收矽粒子混合比例為5:1製備出之複合材料的電極表現最佳，此電極的首次鋰化電容量為2647 mAh g-1，經過51次循環後，電容量保持率57 %。
另外，我們在製備碳/矽複合材料中加入乙醇(95%)以探討溶劑對於電池循環表現的影響。碳/矽複合材料在乙醇媒介中，其矽晶粒子可能因為與無定型碳之間產生較強的作用力而被均勻包覆於無定型碳層中，此結構會有效地降低碳矽複合材料在電池循環中的體積效應，並增加其導電與穩定性。因此，在製備過程中加入乙醇之碳矽複合材料所製備之電池，其最高首次鋰化電容量可達 3333 mAh g-1，經過51次循環後之電容量衰退率為1%/cycle。本論文中，我們以簡易的方法回收矽晶粒子，並進一步將製備成碳/矽複合材料，此複合材料具有良好的電化學性能，在鋰離子負極材料將會是有潛力的應用。

關鍵字

鋰離子電池負極材料 ； 碳/矽負極材料

並列摘要

The aim of this study is to develop carbon coated Si composites as anode materials from Si slicing slurry for the potential application of Li-ion cells. In our previous study, a hybrid of graphite/carbon coated Si nanoparticles has been developed to overcome the poor cycling stability and low electrical conductivity. In this study, we applied the hybrid rationale to the Si particles recovered from Si ingot slicing slurry. First, the purified Si was mixed up with anhydrous citric acid (ACA) in several ratios to form a series of carbon coated composites. From the results obtained from cycling performance, the carbon coated composites in a 5:1 ratio of ACA to Si exhibited an outstanding performance during cycling test. This electrode displayed first-cycle lithiation specific capacity at 2647 mAh g-1 with 57 % retention after 51 cycles.
Furthermore, we investigated the solvent effect on cycling performance by adding 95% ethanol during calcination. With such medium, the Si powder was wrapped evenly by amorphous carbon layers, might indicating the strong interaction between amorphous carbon and silicon particle. This structure effectively suppressed the volume changes and improved electrical conductivity, leading to a stable cyclability. Hence, the composites showed an enhanced 1st cycle lithiation specific capacity of 3333 mAh g-1 with only 1 %/cycle capacity fading after 51 cycles. The carbon coated Si particles hybrid which was prepared by simple recovering Si slicing slurry possessed distinguished electrochemical performance, may be a promising application for Si-based anode materials of Li-ion cells.

並列關鍵字

Lithium-ion battery ； Carbon coated Si materials

參考文獻

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