Influence of Synthesis Conditions on the Capacitance Performance of Hydrothermally Prepared MnO<sub>2</sub> for Carbon Xerogel-Based Solid-State Supercapacitors
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<sub>4</sub> and MnSO<sub>...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Gels |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2310-2861/11/1/68 |
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| Summary: | 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<sub>4</sub> and MnSO<sub>4</sub>·H<sub>2</sub>O 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 K<sub>1.39</sub>Mn<sub>3</sub>O<sub>6</sub> and a very small amount of α-MnO<sub>2</sub> was formed. At higher temperatures (120–160 °C), the amount of α-MnO<sub>2</sub> 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<sup>2</sup>/g). These two-phase (α-MnO<sub>2</sub>/K<sub>1.39</sub>Mn<sub>3</sub>O<sub>6</sub>) 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<sub>+</sub>-form Aquivion<sup>®</sup> 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. |
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| ISSN: | 2310-2861 |