Zhang Dazhi, Dai Jiamian, Zhang Jiajia, Zhang Yixin, Liu Honglai, Xu Yunhui, Wu Jianjun, Li Peipei
School of Chemical Engineering & Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, P. R. China.
Xuzhou College of Industrial Technology, Xuzhou 221114, Jiangsu, P. R. China.
ACS Omega. 2024 Apr 12;9(16):18032-18045. doi: 10.1021/acsomega.3c09725. eCollection 2024 Apr 23.
Spherical δ-MnO nanoflower materials were synthesized via a facile one-step coprecipitation method through adjusting the molar ratio of KMnO to MnSO. The influence of the molar ratio of the reactants on the crystal structure, morphology, and electrochemical performances was investigated. At a molar ratio of 3.3 for KMnO to MnSO, the spherical δ-MnO nanoflowers composed of nanosheets with the highest specific surface area (228.0 m g) were obtained as electrode materials. In the conventional three-electrode system using 1 M NaSO as an electrolyte, the specific capacitance of the spherical δ-MnO nanoflowers reached 172.3 F g at a current density of 1 A g. Moreover, even after 5000 cycles at a current density of 5 A g, the GCD curves remained essentially unchanged, and the specific capacitance still retained 86.50% of the maximum value. The kinetics of the electrode reaction were preliminarily studied through the linear potential sweep technique to observe diffusion-controlled contribution toward total capacitance. For the spherical δ-MnO nanoflower electrode material, diffusion-controlled contribution accounted for 65.1% at low scan rates and still remained significant at high scan rates (100 mV s), indicating excellent utilization efficiency of the bulk phase. The as-fabricated asymmetric supercapacitor HFC-7//MnO-3.3-ASC presented a prominent specific energy of 16.5 Wh kg at the specific power of 450 W kg. Even when the specific power reached 9.0 kW kg, the energy density still retained 9.5 Wh kg.
通过调节高锰酸钾与硫酸锰的摩尔比，采用简便的一步共沉淀法合成了球形δ-二氧化锰纳米花材料。研究了反应物摩尔比对晶体结构、形貌和电化学性能的影响。在高锰酸钾与硫酸锰的摩尔比为3.3时，获得了由具有最高比表面积（228.0 m²/g）的纳米片组成的球形δ-二氧化锰纳米花作为电极材料。在以1 M硫酸钠为电解质的传统三电极体系中，球形δ-二氧化锰纳米花在电流密度为1 A/g时的比电容达到172.3 F/g。此外，即使在5 A/g的电流密度下循环5000次后，恒流充放电曲线基本保持不变，比电容仍保留最大值的86.50%。通过线性电位扫描技术初步研究了电极反应动力学，以观察扩散控制对总电容的贡献。对于球形δ-二氧化锰纳米花电极材料，在低扫描速率下扩散控制贡献占65.1%，在高扫描速率（100 mV/s）下仍很显著，表明体相具有优异的利用效率。制备的不对称超级电容器HFC-7//MnO-3.3-ASC在比功率为450 W/kg时具有16.5 Wh/kg的突出比能量。即使比功率达到9.0 kW/kg，能量密度仍保留9.5 Wh/kg。
