超薄MnO_x修饰多孔碳纳米纤维及其电容脱盐

Ultrathin MnO_x-modified porous carbon fiber for capacitive desalination

MnO_2具有较高的理论比电容而作为良好的电容器材料,但因其导电性和循环稳定性较差,从而限制其电化学应用。本研究以静电纺丝技术制备的多孔碳纳米纤维(PCNF)为载体,经KMnO4浸泡后,高温退火获得超薄MnO_x层修饰的复合碳纳米纤维(APCNF-MnO_x)。通过接触角、SEM、TEM、电化学表征及电容脱盐测试对比分析了碳纤维多孔结构对MnO_x形貌及电化学性能的影响。电化学测试结果表明:APCNF-MnO_x电极的比电容是退火的MnO_x修饰无孔碳纳米纤维(ACNF-MnO_x)电极的4倍(20mV/s)。以APCNF-MnO_x为电容器负极材料,成功制得电容器去离子器件,其电容脱盐量达到9.23mg/g,比ACNF-MnO_x提高了29%。

MnO2 has been used as a capacitor material owing to its high theoretical specific capacitance,however,its poor conductivity and cycle stability limits its electrochemical applications.The annealed ultrathin MnOx-modified porous carbon nanofiber(APCNF-MnOx)was successfully fabricated by self-incubation of electrospun porous carbon nanofibers(PCNF)in KMnO4 solution and followed by heat treatment.The effects of porosity of the carbon fiber on the morphology of MnOx and the electrochemical properties were comparatively studied by contact angle test,SEM,TEM and electrochemical characterization.The electrochemical results demonstrate that the APCNFMnOxelectrode can keep high capacitance retention,with the specific capacity 4 times higher(20 mV/s)than that of the annealed MnOx-modified nonporous carbon nanofiber(ACNF-MnOx).The APCNF-MnOx,as a cathode,is applied successfully for capacitive desalination.The desalination amount of the capacitor reaches 9.23 mg/g,which is 29% higher than that of ACNF-MnOx.