软硬双模板法制备双介孔炭及其储锂性能研究  

Soft and hard templates preparation of bimodal mesoporous carbons and its lithium storage properties

作　　者：孙兵 唐文[1,2] 丛野 袁观明[1,2] 李轩科[1,2] Sun Bing;Tang Wen;Cong Ye;Yuan Guanming;Li Xuanke(State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China;Hubei Coal Conversion and New Carbon Materials Key Laboratory,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉430081 [2]武汉科技大学煤转化与新型炭材料湖北省重点实验室,湖北武汉430081

出　　处：《武汉科技大学学报》2018年第4期276-284,共9页Journal of Wuhan University of Science and Technology

基　　金：国家自然科学基金资助项目(51472186)

摘　　要：以中间相沥青为前驱体,三嵌段共聚物F127和纳米CaCO_3分别为软硬模板剂,采用有机-无机自组装方式制备双介孔炭(BMCs)用作锂离子电池负极材料。借助XRD、Roman、SEM、TEM、氮气吸脱附及恒电流充放电测试对所制双介孔炭材料的结构、形貌及电化学性能进行了表征,研究了软硬模板剂比例与热处理温度对其孔结构及电化学性能的影响。结果表明,当中间相沥青、三嵌段共聚物F127、纳米CaCO_3质量比为2∶1∶7时,所制备的双介孔炭材料电化学性能最佳,在100 mA/g的电流密度下,该材料首次放电比容量可达563.2 mAh/g,100次循环容量保持率为81.25%,在2000 mA/g的电流密度下,其放电比容量为206.3mAh/g;随着热处理温度的升高,双介孔炭孔道结构逐渐坍塌,其可逆储锂容量不断降低,在热处理温度为1800℃时降到最低值,当热处理温度进一步升高达到2300℃以上时,因石墨微晶排列有序度大幅提高,有利于锂离子的嵌入脱出,由此导致材料的可逆储锂容量又开始不断增加。热处理温度低于2300℃时,材料的储锂容量主要取决于其内部缺陷及孔隙,在2300℃及更高温度进行热处理时,材料的储锂容量主要为层间插锂容量。Bimodal mesoporous carbons（BMCs）were prepared by using mesophase pitch as precursor,pluronic F127 and nanosized CaCO3 as soft and hard templates through organic/inorganic self-assembly method and used as anode materials.The structure and morphology of the samples were characterized by XRD,Raman,SEM,TEM and N2 adsorption-desorption isotherms.The electrochemical performances of the samples were analyzed by cyclic voltammetry（CV）and galvanostatic charge-discharge（GCD）.The effects of the ratio of templates and heat treatment temperatures on the porous structure and crystal structure of bimodal mesoporous carbons were investigated.The results show that ratio of templates and heat treatment temperature significantly affect the porous structure and crystal structure.BMCs prepared with the template ratio of 2∶1∶7 at a low temperature manifest good electrochemical performance.As anode materials for lithium-ion batteries,BMCs exhibit a reversible capacity of 563.2 mAh/g at a current density of 100 mA/g during 100 cycles.Meanwhile,BMCs deliver high-rate capability with 206.3 mAh/g at 2000 mA/g and long-term cyclability with a capacity retention of 81.25%after 100 cycles.In the subsequent heat treatment process,the reversible capacity decreases first and then increases with the increase of heat treatment temperature due to the collapse of porous structure and growth of crystallite.At 1800 ℃,it decreases to the lowest.In addition,the reversible capacity of BMCs treated below 2300 ℃is mainly contributed by the defects and pores,and when the heat treatment temperature exceeds 2300℃,the reversible capacity begins to increase which is because of electrochemical insertion of Li＋ions into graphene layers.

关 键 词：中间相沥青 介孔炭 锂离子电池 负极材料 双模板法 储锂性能 电化学性能 

分 类 号：O613.71[理学—无机化学]