晶须形中空多孔氮掺杂复合碳电极材料的制备及电化学性能研究

Preparation and electrochemical properties of whisker-shaped hollow porous nitrogen-doped composite carbon electrode materials

中空多孔碳因其低密度、大孔容、高比表面积以及优良的电导率,被视为一种理想的电负极材料。以纳米碳酸钙晶须为模板剂,负载聚多巴胺薄膜与氧化石墨烯,作为碳源与氮源,制备出晶须形中空多孔碳材料(Cw-GO),应用于锂离子电池负极。碳化过程中,碳酸钙晶须经高温分解释放出大量二氧化碳,刺破碳前体壳层,具有高效扩孔功能。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、氮气吸附-脱附仪对样品形貌和结构进行了表征,利用循环伏安(CV)、阻抗谱(EIS)、循环充放电(GCD)对样品进行电化学性能检测。结果表明,复合材料Cw-GO在500 mA·g^(-1)的电流密度下,其初始放电比容量可达到1185.9 mA·h·g^(-1),在循环200次后,比容量为921.8mA·h·g^(-1),库仑效率基本保持在99.4%,表现出优异的电化学性能。

Hollow porous carbon is considered as an ideal material for the negative electrode due to its low density,large pore volume,high specific surface area and good electrical conductivity.A facile approach for preparing hollow whisker porous carbon material(Cw-GO)for the negative electrode of Lithium-ion battery is proposed by using polydopamine and graphene oxide as carbon and nitrogen source,and CaCO3 whisker as a template agent.The activator CO2,is generated from whisker template and make a great contribution to high specific surface area(SSA)during carbonizing process.The morphology and structure of sample are characterized by transmission electron microscopy(TEM),scanning electron microscopy(SEM)and volumetric adsorption analyzer.The electrochemical characteristics of sample is investigated by cyclic voltammetry(CV),impedance spectroscopy(EIS)and cyclic charge-discharge(GCD).Cw-GO shows the first discharge capacity of 1185.9 mA·h·g?1 under the current density of 500 mA·g?1,and decreased to 921.8 mA·h·g?1 through 200 cycles,the coulomb efficiency remains at 99.4%.