多孔纳米碳球的制备及其电化学性能研究

Study on Synthesis and Electrochemical Performance of Porous Carbon Nano-spheres

以乙炔为碳源,采用CVD法在高温气体环境下裂解制备纳米碳球,进而以KOH为活化剂,将不同比例的KOH与纳米碳球混合进行热活化处理制备多孔纳米碳球,用于锂离子电池负极材料,碱碳比分别为2∶1、3∶1、4∶1。通过SEM、TEM、XRD、BET等对制备的多孔纳米碳球的微观形貌和结构进行表征,通过恒流充放电测试仪对材料的电化学性能进行测试。结果表明:适当的碱碳比处理有利于提高材料的电化学性能,当碱碳比为3∶1时制备的多孔纳米碳球具有较优的电化学性能,其在200 m A/g电流密度下的首次放电比容量能达到1163.5 m Ah/g,首次充电比容量有930.5 m Ah/g,库伦效率为79.98%,在循环100次后比容量维持在420 m Ah/g,有较好的循环性能。

Using acetylene as carbon source,carbon nano-spheres were prepared by CVD method in high temperature gas environment,and then KOH is used as an activator,different proportions of KOH and carbon nano-spheres are mixed and thermal activation treated to prepare porous carbon nano-spheres which are used as anode materials for lithium-ion batteries,the ratios of KOH and carbon nano-spheres are 2∶1,3∶1 and 4∶1,respectively.The structure and surface morphology of porous carbon nano-spheres are characterized by SEM、TEM、XRD、BET and so on.A constant current charge-discharge tester is used to test the electrochemical performance of the material.The results show that:Suitable activating proportion will help improve the electrochemical performance,and when the porous carbon nano-spheres prepared at the activation ratio of 3∶1 have superior electrochemical properties.It shows that at 200 m A/g current density,the initial discharge and charge specific capacity can reach 1163.5 m Ah/g and 930.5 m Ah/g respectively.Coulombic efficiency reached 79.98%.After 100 cycles,it still has a discharge specific capacity of 420 m Ah/g,which shows cycling performance well.