| 有序介孔硅包碳复合结构的制备及其储锂行为 |
| Preparation and Li+-Storage Behaviour of Ordered Mesoporous Si/C Composite Structure |
|
| 摘要: 以P123嵌段模板法合成SiO2-有序介孔（SiO2-OMPs）短棒状结构，以此为前驱体通过镁热还原和酚醛树脂碳包覆处理，成功制备出有序介孔硅/碳复合结构（Si/C-OMPs），用于锂离子电池负极材料测试。从扫描电镜图（SEM）和透射电图（TEM）观察发现，SiO2-OMPs形态可以通过HCl溶液浓度有效调控，在高浓度下获得高堆积密度的粒状有序介孔结构，并在镁热还原和碳包覆处理后这种有序介孔结构均得到完美保持。X射线衍射（XRD）数据的分析表明，镁热还原反应包括两步串连反应：Mg和SiO2先反应形成Mg2Si中间相，而后该相再还原剩余SiO2并获得终产物Si。第二步反应属于缓慢的固/固扩散过程，抑制了整个还原反应的完成，导致Si产率低且存在杂质相。电化学测试表明，由于其坚固的结构和畅通的介孔系统，有序介孔Si/C复合结构具有优异的循环稳定性和倍率性能。 |
| 关键词: Si/C复合结构 介孔材料 锂离子电池 负极材料 电化学 |
| 基金项目: 国家自然科学基金（No.51464025）资助项目。 |
| Abstract: In this paper, an ordered mesoporous Si/C composite structure was prepared successfully for the anode materials of Li-ion batteries through the synthesis of SiO2-ordered mesoporous precursor (SiO2-OMPs) by a P123-copolymer templet route and then a magnesiothermic reduction reaction (MRR) for the SiO2-OMPs precursor and ensuing a phenolic-resin based carbon-capsuling treatment. From the observations of SEM/TEM, it is found that the morphology of SiO2-OMPs can be got well-controlled by HCl concentration and obtained a short rod with densified geometrical stacking under high acid concentration, and the ordered mesoporous symmetry kept unchanged perfectly through later MRR and C-capsuling routes. In addition, the detailed and reasonable analyses based on XRD data reveal that MRR process consists of two-step serial reactions:the Mg2Si intermediate formation from Mg and SiO2 reactants and its transition to final Si products by re-reducing SiO2. The slow feature of the solid/solid diffusive reaction in the second step restrains the completion of whole reduction process, resulting in a low yield of silicon and the existence of some impurity phases. Electrochemical measurements show that the ordered mesoporous Si/C composite exhibited excellent cyclic stability and rate performance, which can be attributed to the robust architect and unblocked mesopore system within such composite structure. |
| Keywords: Si/C composite structure mesoporous materials lithium ion battery anode material electrochemistry |
| 投稿时间：2019-12-16 修订日期：2020-02-28 |
| 摘要点击次数: 2035 |
| 全文下载次数: 997 |
| 张林,王静,唐艳平,郭玉忠,黄瑞安.有序介孔硅包碳复合结构的制备及其储锂行为[J].无机化学学报,2020,36(5):893-900. |
| 查看全文 查看/发表评论 下载PDF阅读器 |
| Support information: |
|
|
|
|
|
|
