高稳定性细菌纤维素/碳纳米管/MnO2复合超级电容器电极

High stability bacterial cellulose/carbon nanotube/MnO_(2) composite supercapacitor electrodes

首先,利用细菌纤维素(BC)的两亲分子结构和纳米尺寸效应实现了水中羟基化多壁碳纳米管(简称MWCNT)的有效分散;接着,利用BC的三维多孔及柔性支架结构和MWCNT的优良导电性,采用真空抽滤辅助自组装构建了BC/MWCNT复合膜;然后,在BC/MWCNT复合膜上电沉积MnO_(2)构建了BC/MWCNT/MnO_(2)复合膜电极。采用SEM、TEM、XRD、Raman光谱及XPS对BC/MWCNT复合膜及BC/MWCNT/MnO_(2)复合膜电极进行了表征,测试了其力学性能及电化学性能。结果表明,BC和MWCNT通过氢键紧密结合协同赋予复合膜优良的电导率和力学性能。BC/MWCNT复合膜的多孔结构、电解质吸收特性及蜂窝状活性MnO_(2)纳米片的桥连结构赋予其出色的电化学性能和循环稳定性,在1 mA/cm^(2)的电流密度下,BC/MWCNT/MnO_(2)-20(电沉积时间20 min)的面积比电容和质量比电容分别达到1.17 F/cm^(2)和200 F/g,在20 mA/cm^(2)的电流密度下进行10000次循环后,其比电容保留率为96%。BC/MWCNT/MnO_(2)复合膜电极的制备简便且成本低廉,在开发柔性储能器件方面具有应用潜力。

Effective dispersion of hydroxylated multi-walled carbon nanotubes(MWCNT for short)in water was achieved utilizing the amphiphilic molecular structure and nano-size effect of bacterial cellulose(BC).BC/MWCNT composite films were then constructed by vacuum filtration assisted self-assembly based on three-dimensional porous and flexible scaffold structure of BC and excellent conductivity of MWCNT.Finally,novel BC/MWCNT/MnO_(2) composite film electrodes were constructed by electrodeposition of MnO_(2) on the BC/MWCNT composite films.BC/MWCNT composite film and BC/MWCNT/MnO_(2) composite film electrodes were characterized by SEM,TEM,XRD,Raman spectrum and XPS,and evaluated for their mechanical and electrochemical properties.The results showed that BC and MWCNT were closely bonded through hydrogen bonds to confer excellent electrical conductivity and mechanical properties.The porous structure of BC/MWCNT composite film,the electrolyte absorption characteristics and the bridge structure of honeycomb active MnO_(2) nanosheets endowed it excellent electrochemical performance and remarkable cycling stability.At a current density of 1 mA/cm^(2),the area specific capacitance and mass specific capacitances of BC/MWCNT/MnO_(2)-20(electrodeposition time of 20 min)reached 1.17 F/cm^(2) and 200 F/g,respectively.And the specific capacitance retention was stable at 96%after 10000 cycles at a current density of 20 mA/cm^(2).The BC/MWCNT/MnO_(2) composite film electrode was facile and inexpensive to prepare and showed great potential in the development of flexible energy storage devices.