凝胶燃烧法合成Li1.07Mn1.93O4纳米片及其高倍率放电和循环稳定性

利用聚乙烯吡咯烷酮（PVP）作为聚合物配位剂和燃料，通过凝胶．燃烧法合成了Li1.07Mn1.93O4纳米片．采用热重／差热分析（TG／DTA）研究了凝胶的燃烧过程．采用X射线多晶衍射（XRD）分析了材料的结构。结果表明合成的Li1.07Mn1.93O4结晶完整，无杂质相．扫描电镜（SEM）结果显示材料的二次形貌为厚度约100nm的片状，由大小约100nm的一次颗粒构成．充放电测试表明Li1.07Mn1.93O4纳米片具备极佳的倍率放电性能和优秀的循环性能．0．5C（1C=120mA·g^-1）倍率的初始放电容量为115．4mAh·g^-1，即使倍率增大到40C，放电容量仍有105．3mAh·...

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Published in物理化学学报 Vol. 28; no. 2; pp. 349 - 354
Main Author 毛景 代克化 翟玉春
Format Journal Article
LanguageChinese
Published 东北大学材料与冶金学院,沈阳,110004 2012
Subjects
倍率性能
循环性能
燃烧合成
锂离子电池
锰酸锂
倍率性能
循环性能
Lithium ion battery
Combustion synthesis
Cycling stability
Lithium manganese oxide
燃烧合成
锂离子电池
锰酸锂
Rate capability
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Summary:利用聚乙烯吡咯烷酮（PVP）作为聚合物配位剂和燃料，通过凝胶．燃烧法合成了Li1.07Mn1.93O4纳米片．采用热重／差热分析（TG／DTA）研究了凝胶的燃烧过程．采用X射线多晶衍射（XRD）分析了材料的结构。结果表明合成的Li1.07Mn1.93O4结晶完整，无杂质相．扫描电镜（SEM）结果显示材料的二次形貌为厚度约100nm的片状，由大小约100nm的一次颗粒构成．充放电测试表明Li1.07Mn1.93O4纳米片具备极佳的倍率放电性能和优秀的循环性能．0．5C（1C=120mA·g^-1）倍率的初始放电容量为115．4mAh·g^-1，即使倍率增大到40C，放电容量仍有105．3mAh·g^-1．在10C倍率的放电条件下，循环850次容量保持率为81％．电化学阻抗谱（EIS）测试表明Li1.07Mn1.93O4纳米片的界面电荷转移电阻（Rct）远小于同类商业材料．
Bibliography:11-1892/06
MAO Jing DAI Ke-Hua ZHAI Yu-Chun （School of Materials and Metallurgy, Northeastern University, Shenyang 110004, P. R. China）
Lithium ion battery; Lithium manganese oxide; Combustion synthesis; Rate capability; Cycling stability
Li1.07Mn1.93O4 nanoflakes were synthesized by a gel-combustion method using polyvinylpyrrolidone （PVP） as the polymer chelating agent and fuel. Thermogravimetric and differential thermal analyses （TG/DTA） were used to investigate the combustion process of the gel precursor. X-ray diffraction （XRD） analysis indicated that the as-prepared Li1.07Mn1.93O4 was a pure, highly crystalline phase. Scanning electron microscopy （SEM） results showed that most of the secondary particles were nanoflakes, about 100 nm in thickness, and the primary particle of the nanoflakes was about 100 nm in size. Charge and discharge tests suggested that the Li1.07Mn1.93O4 nanoflakes had excellent rate capability and good cycling stability. The initial discharge capacity was 115.4 mAh g-1 at a rate of 0.5C
ISSN:1000-6818
DOI:10.3866/PKU.WHXB201112052