热处理对二氧化锰电化学行为的影响.pdf

物理化学学报( Wuli Huaxue Xuebo
April
Acta Phys. -Chim. Sin. 2011, 27(4), 893-899
Article
whxb,pku. edr
热处理对二氧化锰电化学行为的影响
米娟王玉婷高鵬程李文翠
(大连理工大学化工学院,辽守大连116024)
摘要:以高锰酸钾和醋酸锰为前驱体,通过液相沉淀法合成得到二氧化锰.在不同温度热处理条件下研究二
氧化锰的结构转变及其作为超级电容器电极材料的电化学行为.采用X射线衍射(XRD),扫描电镜(SEM),氮气
物理吸附和热重(TG)等手段表征产物的结构特点;采用循环伏安和恒流充放电等方法表征其电化学行为.结果
表明:合成的二氧化锰是具有中孔特征的a-MnO2,比表面积为253m3?g-1,颗粒尺寸在50-100nm之间.350°C
以下的低温热处理使氧化锰仍能保持q-MnO2的晶体结构,比表面积为170m3?g'左右,单电极比电容值由原
来未热解时的267F?g1增加到250°C热处理后的286F?g.高温热处理(4509C)导致氧化锰逐渐过渡为
aMn2O,且表面积下降约为30m2·g1,比电容急刷下降.低温热处理后氧化锰的电化学稳定性明显提高,在
50mV·s'的快速扫描速率下,电极員有良好的倍率特性
关键词:二氧化锰;超级电容器;电极材料;热处理
中图分类号:O646
Effects of Thermal Treatment on the Electrochemical Behavior of
Manganese Dioxide
WANG Yu-ting GAO Peng-cheng LI Wen-ci
School of Chemical Engineering, Dalian Univer ity of Technology, Dalian 116024, Liaoning Province, P. R. China
Abstract: Manganese diide( n )was s thesize using a fluid phase method with potassiu
permanganate and manganous acetate as precursors. The obtained Mno was treated thermally at
different temperatures The structural transformation of Mno its electrochemical behavior as an electrode
material for use in a supercapacitor were investigated by X-ray diffraction(XRD), scanning electron
microscopy (SEM ), N physical adsorption, thermogravimetry(TG), cyclic voltammetry, and galvanostatic
charge-discharge. The results indicate that the synthesized Mno can be assigned to its a phase and that
it possesses a mesoporous feature with a high surface area of up to 253 m.g. After a low temperature
thermal treatment(<350 C), the manganese oxide retained its a-mno crystal structure and its specific
surface area was found to be approximately 170 m.g. The specific capacitance of the sinle electrode
icreased from 267 Fg for untreated Mno2 to 286 Fg for the sample treated at 250 C. However, high
temperature thermal treatment (450 C)results in a transformation of the manganese oxide structure to
a-mn20 and then to a-mn O,. Additionally, the surface area reduced to ca 30 m? g 1 and this lead to a
dramatic decrease in the specific capacitance of manganese oxide. The electrochemical cycling stabilit
of manganese oxide improved noticeably after low temperature thermal treatment and the electrode
retained a good rate performance at a scan rate of 50 mv.s
Key Words: Manganese dioxide upercapaci or Electrode material; Thermal treatment
Received: November 17, 2010; Revised: January 23, 201]; Published on Web: March 14, 2011
Corresponding author. Email: wencuili(dlut. edu.cn; Tel: +86-411-84986140
The project was supported by the Program for New Century Excellent Talents in University of the Ministry of Education of China(Ncet-08-0075)
教育部新世纪优秀人才计划 (NCET-08-0075)资助项目
C Editorial office of Acta Physico-chimica Sinica