Ilcheva Vania, Boev Victor, Dimitrova Mariela, Mladenova Borislava, Karashanova Daniela, Lefterova Elefteria, Rey-Raap Natalia, Arenillas Ana, Stoyanova Antonia
Institute of Electrochemistry and Energy Systems, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 10, 1113 Sofia, Bulgaria.
Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl.109, 1113 Sofia, Bulgaria.
Gels. 2025 Jan 15;11(1):68. doi: 10.3390/gels11010068.
In this study, the potential to modify the phase structure and morphology of manganese dioxide synthesized via the hydrothermal route was explored. A series of samples were prepared at different synthesis temperatures (100, 120, 140, and 160 °C) using KMnO and MnSO·HO as precursors. The phase composition and morphology of the materials were analyzed using various physicochemical methods. The results showed that, at the lowest synthesis temperature (100 °C), an intercalation compound with composition KMnO and a very small amount of α-MnO was formed. At higher temperatures (120-160 °C), the amount of α-MnO increased, indicating the formation of two clearly distinguished crystal structures. The sample obtained at 160 °C exhibited the highest specific surface area (approximately 157 m/g). These two-phase (α-MnO/KMnO) materials, synthesized at the lowest and highest temperatures, respectively, and containing an appropriate amount of carbon xerogel, were tested as active mass for positive electrodes in a solid-state supercapacitor, using a Na-form Aquivion membrane as the polymer electrolyte. The electrochemical evaluation showed that the composite with the higher specific surface area, containing 75% manganese dioxide, demonstrated improved characteristics, including 96% capacitance retention after 5000 charge/discharge cycles and high energy efficiency (approximately 99%). These properties highlight its potential for application in solid-state supercapacitors.
在本研究中，探索了通过水热法合成的二氧化锰的相结构和形态的改性潜力。使用KMnO和MnSO·HO作为前驱体，在不同的合成温度（100、120、140和160°C）下制备了一系列样品。采用各种物理化学方法分析了材料的相组成和形态。结果表明，在最低合成温度（100°C）下，形成了组成为KMnO的插层化合物和极少量的α-MnO。在较高温度（120-160°C）下，α-MnO的量增加，表明形成了两种明显不同的晶体结构。在160°C下获得的样品表现出最高的比表面积（约157 m/g）。分别在最低和最高温度下合成的这两种两相（α-MnO/KMnO）材料，并含有适量的碳干凝胶，使用钠型Aquivion膜作为聚合物电解质，测试其作为固态超级电容器正极活性物质的性能。电化学评估表明，比表面积较高、含有75%二氧化锰的复合材料表现出改进的特性，包括在5000次充放电循环后电容保持率为96%以及高能效（约99%）。这些特性突出了其在固态超级电容器中的应用潜力。
