| 硫系锗基电极材料的制备与研究 |
| 其他题名 | 化学工程
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| 付林
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| 导师 | 二次电池，锗基负极材料，Cu2GeS3，锂活化，[Cu8Ge6Se19](C5H12N)6
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| 2017-05-23
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| 学位授予单位 | 中科院青岛生物能源与过程研究所
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| 学位授予地点 | 青岛
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| 学位专业 | 电动车和便携式电子产品消费市场的迅猛发展，使得高能量密度二次电池的需求全球性的增加。二次电池的能量密度主要取决于电极材料体系，也就是说研发新型高比容量负极材料对获得高能量密度二次电池是必要的。锗基材料由于其迷人的理论比容量（Li4.4Ge：1600 mAh/g，NaGe：369 mAh/g）被作为二次电池负极材料广泛研究。在本论文中，我们致力于研究高性能硫系锗基负极材料，主要研究内容包括以下几个方面：
（1）通过水热法和硫化处理法成功制备三元锗基硫化物Cu2GeS3（CGS），第一次将CGS作为锂离子电池负极材料并研究它的电化学性能。结果证明CGS展现出卓越的循环稳定性（第2至第200次循环之间的容量损失率仅为0.079%）和高倍率容量。优异的电化学性能可以归因于CGS良好的锂离子扩散速率，以及材料的纳米结构能缓解充放电过程中的体积变化。更重要的是，这项工作为研发高性能锗基锂离子电池负极材料提供了一种新的选择。
（2）锂活化能诱发CGS无定型化，促进钠离子的固态扩散从而改善CGS的钠存储性能。CGS的锂活化通过单次嵌锂/脱锂处理实现，活化的CGS（a-CGS）在循环稳定性上展示出引人注目的改善（以100 mA/g的电流密度60次循环后，a-CGS的比容量比CGS提高约110 mAh/g）。当与Na3V2(PO4)3正极匹配组装全电池时，跟Na3V2(PO4)3/CGS对比，Na3V2(PO4)3/a-CGS全电池展现了良好的容量保持率（在100 mA/g的电流密度下，100次循环后的容量保持率由7%提高到86.9%），更好的倍率容量和更高的库伦效率。
（3）晶体构架材料是一种潜在的锂/钠离子电池负极材料。在该部分工作中，我们通过溶剂热法成功合成结晶[Cu8Ge6Se19](C5H12N)6（CGSe）材料，并探索它作为负极材料在锂/钠离子电池中的应用。晶体结构分析显示样品中存在相互连接的三维通道，孔状的结构有利于电解液的渗透和促进锂/钠离子的固态扩散。这项研究开启了结晶构架材料今后在二次电池中的探索。
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| 关键词 | 电化学
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| 摘要 | 中文 |
| 其他摘要 | Electrical vehicle and portable electronic markets are experiencing explosive growth, which increase the global demands for secondary batteries with high energy density. The energy density of secondary batteries is mainly determined by the employed material systems. It is necessary to develop novel anode materials with high capacities to achieve high energy density of secondary batteries performances. Germanium-based materials have been investigated extensively as anodes for high energy density secondary batteries owing to their fascinating theoretical specific capacities (1600 mAh/g for Li4.4Ge, 369 mAh/g for NaGe ). In this paper, we focused our attention on Ge-based chalcogenide anode materials with high performances. The concrete research contents are summarized as follows:
(1) The ternary Ge-based sulfides Cu2GeS3 (CGS) were successfully prepared via a hydrothermal method and sulfuration treatment. We study the electrochemical performance of CGS as an anode for lithium ion batteries for the first time. The results demonstrated that the CGS delivered excellent stable cycle property (only 0.079% capacity loss from the 2nd to 200th cycle) and high rate capability. These excellent properties can be ascribed to the favourable Li+ diffusion coefficient of CGS, and the nanostructured CGS which can accommodate large volume change during the charge/discharge process. More importantly, this work offers a new option to develop Ge-based anode materials for high performance lithium ion batteries.
(2) Activation with Li induces amorphization of CGS and accelerates solid-state diffusion of sodium ion that improves the sodium storage properties of CGS. Li activation of CGS was performed by a single lithiation/delithiation cycle. The actived CGS (a-CGS) demonstrates a dramatic improvement in cycling stability (the specific capacity of a-CGS is higher than that of CGS about 110 mAh/g after 60 cycles at current density of 100 mA/g). When applied to a full cell by coupling a Na3V2(PO4)3 cathode, the assembled Na3V2(PO4)3/a-CGS full cell exhibits favorable capacity retention (the capacity retention was enhanced from 7% to 86.9% after 100 cycles at current density of 100 mA/g), better rate capability and higher coulombic efficiency compared with Na3V2(PO4)3/CGS full cell.
(3) The crystalline framework material is a promising lithium/sodium ion batteries anode materials. In this work, we report the successful synthesis of a crystalline [Cu8Ge6Se19](C5H12N)6 (CGSe) material via a solvothermal method and explore their application as anode materials for lithium/sodium ion batteries. The crystal structure analysis shows that the as-prepared sample has 3D interconnected channels. The porous structures is beneficial for good electrolyte penetration and accelerates solid-state diffusion of lithium/sodium ion. This investigation will open up a new exploration of crystalline framework materials for secondary batteries in the future. |
| 作者部门 | 仿生能源与储能系统团队 |
| 公开日期 | 2017-06-30
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| 学位类型 | 硕士
; 学位论文
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| 语种 | 中文
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| 文献类型 | 学位论文
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| 条目标识符 | http://ir.qibebt.ac.cn/handle/337004/9973
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| 专题 | 仿生与固态能源系统研究组
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| 作者单位 | 中科院青岛生物能源与过程研究所
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推荐引用方式
GB/T 7714 |
付林. 硫系锗基电极材料的制备与研究[D]. 青岛. 中科院青岛生物能源与过程研究所,2017.
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