基于水溶性煤沥青的MnO@C复合材料的制备及储锂性能研究  

Preparation and Lithium Storage Properties of MnO@C Composites Based on the Water Soluble Pitches

作　　者：刘渤 周卫民[1] 陈燕[2] 王坤 张殿浩 张文武 孟祥安 王士戈 安百钢[1] 徐桂英[1] LIU Bo;ZHOU Wei-min;CHEN Yan;WANG Kun;ZHANG Dian-hao;ZHANG Wen-wu;MENG Xiang-an;WANG Shi-ge;AN Bai-gang;XU Gui-ying(Key Laboratory of Energy Materials and Electrochemistry Research Liaoning Province,University of Science and Technology Liaoning,Liaoning Anshan 114051,China;School of Mechanical Engineering and Automation,University of Science and Technology Liaoning,Liaoning Anshan 114051,China;Haicheng Shenhe Technology Co.,Ltd.,Liaoning Anshan 114200,China)

机构地区：[1]辽宁科技大学辽宁省能源材料与电化学重点实验室,辽宁鞍山114051 [2]辽宁科技大学机械工程与自动化学院,辽宁鞍山114051 [3]海城申合科技有限公司,辽宁鞍山114200

出　　处：《表面技术》2023年第1期298-305,324,共9页Surface Technology

基　　金：辽宁省教育厅项目(LJKQZ2021126)。

摘　　要：目的制备出具有高容量、良好的倍率性能和循环稳定性的MnO@C复合电极材料。方法使用水溶性煤沥青及KMnO4为原料,通过水热法制备出Mn3O4@C前驱体。然后经过高温碳热还原制备MnO@C复合电极材料。通过SEM、XPS、XRD和Raman等分析技术对MnO@C复合材料的形貌、表面、结构等进行表征,并使用循环伏安、恒流充放电和电化学阻抗等电化学分析技术对其电化学性能进行了评价。结果TEM和SEM结果表明,制备的水溶性煤沥青表面丰富的含氧官能团与MnSO4溶液中的Mn2+之间有较强的相互作用,提供成核位点,进而促进了后续MnO@C材料中纳米颗粒的形成和均匀生长。这些纳米粒子的形成又起到了提升MnO@C电化学性能的作用。XRD、Raman和XPS结果表明,Mn3O4@C前驱体经过高温碳热还原反应生成MnO@C后,在MnO表面和包覆的碳材料之间生成了大量的Mn—O—C键。电化学结果表明,MnO@C电极在0.1 A/g电流密度下循环100圈后具有606.47 mAh/g较高的储锂容量,即使是在0.5 A/g大电流密度下循环400圈后仍具有293.83 m Ah/g的储锂容量。同时,电化学测试也表明,MnO@C复合材料具有非常好的倍率性能。结论使用鞍钢产的煤沥青根据混酸法制备了水溶性煤沥青。通过使用水溶性煤沥青和KMnO4成功地制备了Mn3O4@C前驱体。以Mn3O4@C前驱为原料,通过高温碳热还原法制备了MnO@C复合材料。在MnO表面包覆碳层不仅提供活性位点而且起到限制在充放电过程中MnO体积膨胀的作用。特别值得注意的是,Mn—O—C键构筑了MnO和碳层之间的快速导电通道,提升了电极反应动力学。The aim of this research is to realize the constructions of Mn—O—C bonds by covering the coal tar pitch based carbon materials on the surface of MnO.The formations of Mn—O—C bonds play the main role to construct the conductive network so as to diminish the interfacial resistance,which causes that the prepared MnO@C materials possesses the excellent electrochemical performances such as high Li+storage capacity,excellent rate performances and long cycle performances.Based on the hydrothermal method,the Mn3O4@C precursors are synthesized by using the water soluble coal tar pitches(WSP)and KMnO4.The MnO@C materials are synthesized by the carbothermic reduction reaction methods using the Mn3O4@C precursors.The morphologies,surface characteristics and detailed structures of MnO@C materials are verified by the TEM,SEM,XPS,XRD and Raman measurements.TEM and SEM results indicate that plenty of oxygen-containing functional groups existing in the WSP possess the interactions with the Mn2+of MnSO4solution,which is able to facilitate the formations of cores which are beneficial to accelerate the formations and uniformly growing of nano particles in MnO@C materials.Formations of nano particles are also play the role to enhance the electrochemical performances of MnO@C materials.The XRD,Raman and XPS results indicate that a lot of Mn—O—C bonds formed between the surface of MnO and carbon materials in the MnO@C materials.The electrochemical performances of MnO@C materials were evaluated by cyclic voltammetry,charge-discharge and electrochemical impedance spectroscopy measurements.As a result,it is found that MnO@C shows the storage capacity at606.47 m Ah/g after cycling charge-discharge 100 cycles at a current density of 0.1 A/g.Although the current density was increased to 0.5 A/g,the MnO@C composite materials still show the storage capacity at 293.83 m Ah/g after 400 cycles.Additionally,the fact that MnO@C materials have the tremendous rate performances was also determined in these presented studies.In summarizatio

关 键 词：一氧化锰 水溶性煤沥青 Mn—O—C键 界面阻抗 锂离子电池 负极 

分 类 号：TB43[一般工业技术]