| 引用本文: | 陈淑花,于驰,刘学武.超临界水热制备LiFePO4及煅烧碳包覆改性研究[J].材料科学与工艺,2017,25(2):74-78.DOI:10.11951/j.issn.1005-0299.20160050. |
| CHEN Shuhua,YU Chi,LIU Xuewu.Supercritical hydrothermal method preparation for LiFePO4 followed by calcination carbon-coating[J].Materials Science and Technology,2017,25(2):74-78.DOI:10.11951/j.issn.1005-0299.20160050. |
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| 摘要: |
| 本文以FeSO4、H3PO4和LiOH为原料，采用超临界水热过程制备了亚微米级LiFePO4颗粒.在此基础上，为了提升制备的LiFePO4正极材料的物理和电化学性能，对其进行了后续煅烧碳包覆改性研究.同时，通过XRD、SEM、充放电测试、CV和EIS测试手段，对LiFePO4正极材料改性前后的结构、形貌和电化学性能进行了表征.结果表明：后续固相煅烧碳包覆改性能够显著改善LiFePO4的结晶性能，减小颗粒粒径，降低电荷传递阻抗，以及大幅度地提升放电容量和循环性能；以PVP为模板剂、蔗糖为碳源，700 ℃煅烧1 h得到的LiFePO4/C颗粒粒径小、分布均一，室温0.2 C倍率的首圈放电比容量为153.1 mAh/g，1 C倍率充放电时，放电比容量可保持在144.2 mAh/g，1 C循环50次，容量保持率达到97.1%.
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| 关键词: 超临界水热 磷酸铁锂 固相煅烧 碳包覆 |
| DOI：10.11951/j.issn.1005-0299.20160050 |
| 分类号:O646；TM911 |
| 文献标识码:A |
| 基金项目:国家自然科学基金资助项目(0,5). |
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| Supercritical hydrothermal method preparation for LiFePO4 followed by calcination carbon-coating |
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CHEN Shuhua1, YU Chi1, LIU Xuewu2
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(1.College of Environmental and Chemical Engineering, Dalian University, Dalian 116622, China; 2.School of Chemical Machinery and Safety, Dalian University of Technology, Dalian 116024, China)
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| Abstract: |
| Pure sub-micro LiFePO4 particles were prepared via supercritical hydrothermal process using FeSO4, H3PO4 and LiOH as raw materials, and as-prepared LiFePO4 was calcined and carbon-coated to further promote its physical and electrochemical properties. The structure, morphology and electrochemical performance of LiFePO4 were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), charge and discharge test, cyclic voltammetry (CV) and electrochemical impedance spectra (EIS). The results show that calcination and carbon-coating can effectively improve the crystallization property, decrease the particles size, charge the transfer resistance, and enhance the electrochemical performance of LiFePO4. The LiFePO4/C composites with small particle size and uniform structure were obtained with polyvinyl pyrrolidone (PVP) as template and sucrose as carbon source under the conditions of 1 h calcination at 700 ℃. The initial discharge capacity was 153.1 mAh/g and 144.2 mAh/g at 0.2 C and 1 C, respectively. After 50 cycles, 97.1% of the initial discharge capacity was retained at 1 C rate.
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| Key words: supercritical hydrothermal LiFePO4 calcination carbon-coating |
