CAJ | 학술논문

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Li1.07 Mn1.93O4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100 nm的片状,由大小约100 nm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=120 mA·g-1)倍率的初始放电容量为115.4 mAh·g-1,即使倍率增大到40C,放电容量仍有105.3 mAh·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.
이용취을희필각완동(PVP)작위취합물배위제화연료,통과응효-연소법합성료Li1.07Mn1.93O4납미편.채용열중/차열분석(TG/DTA)연구료응효적연소과정.채용X사선다정연사(XRD)분석료재료적결구,결과표명합성적Li1.07 Mn1.93O4결정완정,무잡질상.소묘전경(SEM)결과현시재료적이차형모위후도약100 nm적편상,유대소약100 nm적일차과립구성.충방전측시표명Li1.07Mn1.93O4납미편구비겁가적배솔방전성능화우수적순배성능.0.5C(1C=120 mA·g-1)배솔적초시방전용량위115.4 mAh·g-1,즉사배솔증대도40C,방전용량잉유105.3 mAh·g-1.재10C배솔적방전조건하,순배850차용량보지솔위81％.전화학조항보(EIS)측시표명Li1.07Mn1.93O4납미편적계면전하전이전조(Rct)원소우동류상업재료.
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 (1 C=120 mAh· g-1) and the capacity was maintained at 105.3 mAh·g-1 at the high discharge rate of 40C.When cycling at 10C,the material retained 81％ of its initial capacity after 850 cycles.Electrochemical impedance spectroscopy (EIS) tests indicated that the charge-transfer resistance (Rct) of the Li1.07 Mn1.93O4 nanoflakes was much less than that of commercial Li1.07Mn1.93O4.