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研究论文

钠锰比对NaxMnO2的性能和钠离子脱嵌过程的影响

  • 谢永纯 ,
  • 王成 ,
  • 蒋芳 ,
  • 杨洋 ,
  • 苏静 ,
  • 龙云飞 ,
  • 文衍宣
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  • 1. 广西大学化学化工学院,广西 南宁 5300042. 广西高校新能源材料及相关技术重点实验室,广西 南宁 5300043. 广西新型电池材料工程技术研究中心,广西 南宁 5300044. 广西有色金属及特色材料加工重点实验室,广西 南宁 530004

收稿日期: 2018-02-07

  修回日期: 2018-03-26

  网络出版日期: 2018-04-25

基金资助

国家自然科学基金资助项目(No. 51564002)资助

Influences of Na-Mn Ratio on Electrochemical Performances and Intercalation-Deintercalation Processes of Sodium Ion in NaxMnO2

  • XIE Yong-chun ,
  • WANG Cheng ,
  • JIANG Fang ,
  • YANG Yang ,
  • SU Jing ,
  • LONG Yun-fei ,
  • WEN Yan-xuan
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  • 1. School of Chemistry of and Chemical Engineering, Guangxi University, Nanning 530004, China;2. Guangxi Key Laboratory of Processing for Non-ferrous Metallic and Featured Materials, Guangxi University, Nanning 530004, China; 3. Guangxi Novel Battery Materials Research Center of Engineering Technology, Nanning 530004, China; 4. Guangxi Colleges and Universities Key Laboratory of Novel Energy Materials and Related Technology, Nanning 530004, China

Received date: 2018-02-07

  Revised date: 2018-03-26

  Online published: 2018-04-25

Supported by

    The National Natural Science Fund(No. 51564002)

摘要

采用高温固相法合成了NaxMnO2,并用X-射线衍射、X-射线光电子能谱、场发射扫描电镜、循环伏安、电化学阻抗谱和恒流充放电技术研究了钠锰比对材料的形态结构、电化学性能和钠离子脱嵌过程的影响. 结果表明,NaxMnO2 主要由Na0.7MnO2 Na0.91MnO2 组成,且Na0.91MnO2 的量随着钠锰比的增加而增加. 随着钠锰比的增加,SEI 膜扩散、界面电化学反应和固相扩散的活化能先减少后增大,而材料的放电比容量则先增大后减少. 当钠锰比为0.80 时,合成的材料1C 倍率下首次放电比容量为152.8 mAh·g-150 次循环容量保持率为80.6%5C 大倍率下放电比容量为88.3 mAh·g-1,表现出了良好的循环性能和倍率性,相应的SEI 膜扩散、界面电化学反应和固相扩散过程的活化能分别为68.2340.07 57.62 KJ·mol-1.

本文引用格式

谢永纯 , 王成 , 蒋芳 , 杨洋 , 苏静 , 龙云飞 , 文衍宣 . 钠锰比对NaxMnO2的性能和钠离子脱嵌过程的影响[J]. 电化学, 2018 , 24(4) : 375 -384 . DOI: 10.13208/j.electrochem.180207

Abstract

In this work, NaxMnO2 was synthesized by a solid-state reaction. The influences of Na:Mn ratio on the structure, morphology and electrochemical performance, and sodium ion intercalation/deintercalation processes were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge test. The prepared NaxMnO2 was mainly composed of Na0.7MnO2 and Na0.91MnO2, and the content of Na0.91MnO2 increased with the increase of Na:Mn ratio. However, the activation energy values of surface membrane diffusion, interfacial electrochemical reaction and Na+ diffusion in the bulk material first decreased and then increased with the increase of Na:Mn ratio, while the discharge capability first increasedand then decreased with the increase of Na:Mn ratio. The sample synthesized with the Na:Mn ratio of 0.80 delivered a discharge capacity of 152.8 mAh·g-1 with a capacity retention of 80.6% after 50 cycles at 1C. Even being charged/discharged at 5C, this sample still provided a discharge capacity of 88.3 mAh·g-1, showing good cycle-stability and rate performance. The activation energy values of surface membrane diffusion, interfacial electrochemical reaction and solid-phase diffusion were found to be 68.23, 40.07 and 57.62 kJ·mol-1, respectively.
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