Time-optimized ultrasonic synthesis of α-MnO2 nanoflower: controlling structural evolution and agglomeration for stable electrochemical performance
- 1Department of Physics, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India
- 2Centre for Advanced Materials Research, Department of Physics, Government College for Women, University of Kerala, Thiruvananthapuram, Kerala 695014, India
Abstract
This study presents a simple ultrasonication-assisted route for the synthesis of α-MnO2 nanoflowers at room temperature. The process employs acoustic cavitation at 40 kHz and 100 W with test synthesis times of 0, 20, 40, and 60 min. The best results were obtained with 40 min of sonication, yielding uniform nanoflower structures with (2 × 2) tunnel framework of α-MnO2, a maximum specific BET surface area of 182 m2 g−1 and total pore volume of 0.41 cm3 g−1. Besides, the electrochemical measurements of α-MnO2 nanoflowers were carried out using a three-electrode configuration, achieving a specific capacitance of 121F g−1 in 1 M Na2SO4 and 116F g−1 in 1 M LiCl electrolytes at 2 mV s−1 for 40 min sonicated sample. Moreover, the electrochemical impedance spectroscopy indicates notable reduction in the charge transfer resistance upon optimization. The fabricated symmetric device exhibits a coulombic efficiency of ∼99% over 10,000 cycles in a 1 M Na2SO4 electrolyte. The ambient, template-free synthesis condition offer clear pathways to industrial scalability. This work establishes sonication duration as a versatile parameter for engineering metal oxides with tailored morphology, delivering reliable performance and long-term stability in neutral aqueous supercapacitors.
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BibTeX
@article{divyalekshmi2026timeoptimized,
title = {{Time-optimized ultrasonic synthesis of α-MnO2 nanoflower: controlling structural evolution and agglomeration for stable electrochemical performance}},
author = {S.V. Divyalekshmi and M.A. Anu and T.S. Xavier and R. Murali},
journal = {Ultrasonics Sonochemistry},
year = {2026},
month = oct,
doi = {10.1016/j.ultsonch.2026.108119},
url = {https://doi.org/10.1016/j.ultsonch.2026.108119},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Time-optimized ultrasonic synthesis of α-MnO2 nanoflower: controlling structural evolution and agglomeration for stable electrochemical performance
AU - S.V. Divyalekshmi
AU - M.A. Anu
AU - T.S. Xavier
AU - R. Murali
PY - 2026
DA - 2026/10/17
JO - Ultrasonics Sonochemistry
DO - 10.1016/j.ultsonch.2026.108119
UR - https://doi.org/10.1016/j.ultsonch.2026.108119
AB - This study presents a simple ultrasonication-assisted route for the synthesis of α-MnO2 nanoflowers at room temperature. The process employs acoustic cavitation at 40 kHz and 100 W with test synthesis times of 0, 20, 40, and 60 min. The best results were obtained with 40 min of sonication, yielding uniform nanoflower structures with (2 × 2) tunnel framework of α-MnO2, a maximum specific BET surface area of 182 m2 g−1 and total pore volume of 0.41 cm3 g−1. Besides, the electrochemical measurements of α-MnO2 nanoflowers were carried out using a three-electrode configuration, achieving a specific capacitance of 121F g−1 in 1 M Na2SO4 and 116F g−1 in 1 M LiCl electrolytes at 2 mV s−1 for 40 min sonicated sample. Moreover, the electrochemical impedance spectroscopy indicates notable reduction in the charge transfer resistance upon optimization. The fabricated symmetric device exhibits a coulombic efficiency of ∼99% over 10,000 cycles in a 1 M Na2SO4 electrolyte. The ambient, template-free synthesis condition offer clear pathways to industrial scalability. This work establishes sonication duration as a versatile parameter for engineering metal oxides with tailored morphology, delivering reliable performance and long-term stability in neutral aqueous supercapacitors.
SN - 1350-4177
SN - 1873-2828
ER -