多孔碳碳化温度对锂硫电池性能的影响  

Effect of porous carbon carbonizing temperature on the properties of Li-S batteries

作　　者：唐琼[1,2] 李合琴[2] 张静[1,2] 左敏[2] 潘媛媛[2] 林志伟[2] 

机构地区：[1]合肥工业大学电子科学与应用物理学院,安徽合肥230009 [2]合肥工业大学材料科学与工程学院,安徽合肥230009

出　　处：《合肥工业大学学报（自然科学版）》2017年第4期466-469,485,共5页Journal of Hefei University of Technology：Natural Science

基　　金：中央高校基本科研业务费专项资金资助项目(4115100010);安徽省高校自然科学基金资助项目(KJ2009A091;KJ2012A228);中国科学院战略性先导科技专项资助项目(XDA03040000)

摘　　要：文章以蔗糖为碳源,纳米碳酸钙为模板在800℃和950℃下碳化生成多孔碳,并分别与单质硫复合成锂硫电池正极材料。用SA3100测试多孔碳在77K的氮气吸脱附等温曲线,分别用Brunauer-Emmett-Teller(BET)理论和Barrett-Joyner-Halenda(BJH)模型计算多孔碳比表面积和孔径分布。采用场发射扫描电子显微镜(field emission scanning electron microscopy,FESEM)观察2种硫碳复合材料的形貌,能谱仪(energy dispersive spectrometer,EDS)观察硫和碳元素分布,X射线衍射仪(X-Ray diffraction,XRD)检测单质硫与碳材料的结构。测试了电池的交流阻抗谱和恒流充放电性能。结果表明:经950℃碳化的多孔碳与硫组成的复合材料在0.2C的放电倍率下首次放电比容为1 327mA·h/g,100次循环后,仍保持在630mA·h/g,库仑效率接近100%。Two kinds of porous carbons were synthesized at carbonizing temperatures of 800℃ and 950 ℃ by using sucrose as carbon precursor and nano-CaCOa as hard template. The cathode materials of Li-S batteries were prepared by porous carbons and sulfur. The nitrogen adsorption isotherms of porous carbons were measured at 77 k with SA3100. The specific surface areas and pore size distributions were calculated according to the Brunauer-Emmett-Teller （BET） theory and Barrett-Joyner- Halenda（BJH） model respectively. The morphologies and element mapping of the composites were determined by field emission scanning electron microscopy（FESEM） and energy dispersive spectrometer（EDS） respectively. The composite structures were characterized by X-ray diffraction（XRD）. The electrochemical properties were characterized by electrochemical impedance spectroscopy and constant current charge and discharge. The results show that the composites consisted of porous carbon carbonized at 950℃ and sulfur exhibit better performances. Its initial discharge specific capacity is up to 1 327 mA·h/g at a current rate of 0. 2C and retains 630 mA·h/g after 100 cycles. The coulombic efficiency is near 100%.

关 键 词：锂硫电池 碳化温度 多孔碳 比表面积 孔容 库仑效率 

分 类 号：TQ152[化学工程—电化学工业]