Conversion of interlocked cube-like Mn3O4 into nanoflakes of layered birnessite MnO2 during supercapacitive studies
Conversion of interlocked cube-like Mn3O4 into nanoflakes of layered birnessite MnO2 during supercapacitive studies
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DOI：
10.1016/j.jallcom.2010.02.014
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发表时间：
2010-04-30
影响因子：
6.2
通讯作者：
Lokhande, C. D.
中科院分区：
文献类型：
--
作者：
Dubal, D. P.;Dhawale, D. S.;Lokhande, C. D.
采用化学浴沉积（CBD）法存款了用于电化学超级电容器的黑锰矿Mn 3 O 4电极。在1 M Na 2SO 4电解液中，在-0.1 ~+0.9V的电位循环过程中，所制备的Mn 3 O 4电极表现出理想的电容行为。X射线衍射（XRD）、扫描电子显微镜（SEM）、拉曼散射（RS）和润湿性研究表明，由于电势循环，晶体Mn 3 O 4的互锁立方体被电化学氧化为层状水钠锰矿MnO 2的纳米片。由于电位循环的作用，Mn 3 O 4薄膜的接触角由亲水性变为超亲水性。研究了电解液浓度和扫描速率对MnO_2薄膜比电容的影响。阻抗分析表明，水钠锰矿MnO 2纳米片比Mn 3 O 4具有良好的导电性，因此可以在广泛的应用范围内使用。在1 M Na 2SO 4电解液中，以5 mV s（-1）的扫描速率扫描时，其比电容最高可达223 Fg（-1），5000次循环后稳定性为90%。(C)2010 Elsevier B. V.保留所有权利。
A facile route based on chemical bath deposition (CBD) from urea containing bath has been developed to deposit the interlocked cubes of hausmannite Mn3O4 electrode for electrochemical supercapacitor application. The as-prepared Mn3O4 electrode showed ideal capacitive behavior during potential cycling within the range of -0.1 to +0.9 V in 1 M Na2SO4 electrolyte. The X-ray diffraction (XRD), scanning electron micrograph (SEM) and Raman scattering (RS) and wettability studies during the supercapacitive stability showed that the interlocked cubes of crystalline Mn3O4 are electrochemically oxidized to nanoflakes of layered birnessite MnO2 due to potential cycling. Due to potential cycling the contact angle of Mn3O4 thin film changed from hydrophilic to superhydrophilic nature. The effect of electrolyte concentration and scan rate on the specific capacitance of so formed MnO2 film has been investigated. Impedance analysis shows that birnessite MnO2 nanoflakes are good conducting than Mn3O4 hence can be used over a wide range of applications. It exhibited highest specific capacitance of 223 Fg(-1) in 1 M Na2SO4 electrolyte at 5 mV s(-1) scan rate and 90% stability after 5000 cycles. (C) 2010 Elsevier B.V. All rights reserved.