低热固相法制备纳米MnO_2/CNT超电容复合电极的循环稳定性(英文)  

Improved Cyclability of Nano-MnO_2/CNT Composite Supercapacitor Electrode Derived from Room-Temperature Solid Reaction

作　　者：胡洁[1] 袁安保[1] 王玉芹[1] 王秀玲[1] 

机构地区：[1]上海大学理学院化学系,上海200444

出　　处：《物理化学学报》2009年第5期987-993,共7页Acta Physico-Chimica Sinica

基　　金：上海市教育委员会重点学科建设项目(J50102)资助

摘　　要：为了改善纳米MnO2超级电容器电极的充放电循环稳定性,以Mn(OAc)2·4H2O、NH4HCO3和碳纳米管(CNT)为原料,采用低热固相反应得到前驱体,再经焙烧和酸处理,制备了一系列CNT含量不同的纳米MnO2/CNT复合电极材料,并用X射线衍射(XRD)、透射电镜(TEM)和Brunauer-Emmett-Teller(BET)比表面积测定方法对其进行了表征.XRD分析结果表明,复合材料中的MnO2为纳米γ-MnO2.研究了复合电极在1mol·L-1LiOH电解质中的电化学性能,并与不含CNT的纯纳米MnO2电极进行了比较.结果表明,含CNTs为10%(w,质量分数,下同)和20%的MnO2/CNT复合电极的循环稳定性远优于纯纳米MnO2电极的循环稳定性,其中含10%CNTs的MnO2/CNT复合电极不仅具有良好的循环稳定性,而且在1000mA·g-1高倍率充放电条件下仍具有200F·g-1的高比电容.To improve the charge/discharge cycle stability of a nanostructured manganese dioxide electrode for supercapacitor applications, a series of nano-MnO2/carbon nanotube （CNT） hybrid electrode materials with different mass fractions of CNTs were prepared. The materials were prepared using a room-temperature solid-grinding reaction between Mn（OAc）2· 4H2O and NH4CO3 in the presence of CNTs to obtain a precursor. This was followed by calcination and an acid-treatment process and the products were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and Brunauer-Emmett-Teller （BET） surface analysis. XRD results indicated that the MnO2 in the composites was nanostructured γ-MnO2. Electrochemical performance of the MnO2/CNT composite electrodes in 1 mol·L^-1 LiOH alkaline aqueous electrolyte was studied and compared to a pure nano-MnO2 electrode without CNTs. The MnO2/CNT composite electrodes with 10% or 20% （w, mass fraction） CNTs showed far superior cycle stability than the pure MnO2 electrode. The MnO2/CNT composite electrode with 10% CNTs exhibited good cycling stability and also a high specific capacitance of 200 F·g^-1 at a high charge/discharge current rate of 1000 mA. g^-1.

关 键 词：纳米MnO2/CNT复合电极 超电容性能 循环稳定性 低热固相法 LiOH电解质 

分 类 号：TM53[电气工程—电器]