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张威龙,李桦林,庞刚,等. 一步法合成碳包覆Na0.44MnO2正极材料的制备及电化学性能[J]. 安徽工业大学学报(自然科学版),2024,41(3):248-255. doi: 10.12415/j.issn.1671-7872.23185
引用本文: 张威龙,李桦林,庞刚,等. 一步法合成碳包覆Na0.44MnO2正极材料的制备及电化学性能[J]. 安徽工业大学学报(自然科学版),2024,41(3):248-255. doi: 10.12415/j.issn.1671-7872.23185
ZHANG Weilong, LI Hualin, PANG gang, ZHANG Qingan. Preparation and Electrochemical Performance of Carbon-coated Na0.44MnO2 Cathode Material Synthesized by One-step Method[J]. Journal of Anhui University of Technology(Natural Science), 2024, 41(3): 248-255. DOI: 10.12415/j.issn.1671-7872.23185
Citation: ZHANG Weilong, LI Hualin, PANG gang, ZHANG Qingan. Preparation and Electrochemical Performance of Carbon-coated Na0.44MnO2 Cathode Material Synthesized by One-step Method[J]. Journal of Anhui University of Technology(Natural Science), 2024, 41(3): 248-255. DOI: 10.12415/j.issn.1671-7872.23185

一步法合成碳包覆Na0.44MnO2正极材料的制备及电化学性能

Preparation and Electrochemical Performance of Carbon-coated Na0.44MnO2 Cathode Material Synthesized by One-step Method

  • 摘要: 以MnCO3为锰源,Na3C6H5O7•2H2O为碳源和钠源,采用一步固相法制备碳包覆Na0.44MnO2(NMO/C)正极材料,对材料的晶体结构、微观组织形貌进行表征分析,探究Na3C6H5O7•2H2O和Na2CO3对Na0.44MnO2晶体结构的影响;采用NMO/C组装纽扣电池进行循环伏安和首圈充放电测试,探究NMO/C材料的电化学性能。结果表明:NMO/C材料具有三维隧道结构,空间群为Pbam,形貌为长棒状,且表面均匀包覆一层2~3 nm的碳层;NMO/C正极材料表现出比较优异的长循环寿命和倍率性能,0.5 C倍率下的首圈放电比容量为113.1 mAh•g−1,循环1 000圈后的放电比容量仍有74.1 mAh•g−1,容量保持率为65.5%;0.1,0.2,0.5,1.0,2.0 C倍率下的放电比容量分别为121.1,115.7,113.4,110.3,103.9 mAh•g−1,这是由于碳包覆层不仅可提高Na0.44MnO2正极材料的导电性,还可阻碍其与电解液直接接触,抑制Mn3+的溶解,致使NMO/C材料表现出优异的电化学性能。

     

    Abstract: Taking MnCO3 as manganese source and Na3C6H5O7•2H2O as carbon and sodium sources,the carbon-coated Na0.44MnO2 (NMO/C) cathode material was prepared by one-step solid-state reaction. Its crystal structure and microstructure morphology were analyzed to explore the influence of Na3C6H5O7•2H2O and Na2CO3 on the crystal structure of NMO/C.The coin cells assembled with NMO/C were constructed the cyclic voltammetry and first charge and discharge tests to investigate the electrochemical performance of NMO/C materials. The results indicate that the NMO/C materials has three-dimensional tunnel structure with the space group of Pbam, and its morphology is a long rod-like particle, which is covered uniformly with 2–3 nm carbon layer. When is used as the cathode material of sodium-ion half cells, the NMO/C cathode materials shows excellent long-term cycling stability and rate performance, with discharge specific capacity of 113.1 mAh•g−1 for the first cycle and 74.1 mAh•g−1 after 1 000 cycles at 0.5 C, which the capacity retention is 65.5%. The discharge specific capacities are 121.1, 117.4, 112.7, 105.6, and 98.3 mAh•g−1 at at rates of 0.1, 0.2, 0.5, 1.0, 2.0 C, respectively. These improvements are attributed to the carbon-coating layer, which can not only effectively improve the electrical conductivity of the Na0.44MnO2, but also hinder its direct contact with the electrolyte and inhibit the dissolution of Mn3+. Therefore, the carbon-coated Na0.44MnO2 cathode material shows excellent electrochemical performance.

     

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