Electrochemical performance of hydrothermally synthesized Co-doped NiO electrodes: effect of propylene carbonate additive and doping concentration
Keywords:
Transition metal oxide, Electrode material, Hydrothermal method, Supercapacitor, Propylene carbonateAbstract
Transition metal oxides have received substantial attention because of their versatile applications in photocatalysis, electronics, and energy storage systems such as batteries and pseudocapacitors. Owing to their variable oxidation states, they are known as redox-active materials, which give rise to battery-type and pseudocapacitor-type electrodes for energy storage devices. In this work, 10%, 20%, and 30% cobalt-doped nickel oxide and 30% cobalt-doped nickel oxide mixed with propylene carbonate (PC) were synthesized via the hydrothermal method to produce electrode materials for a supercapacitor. The electrode materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy--energy-dispersive X-ray spectroscopy (FESEM--EDX), and Brunauer--Emmett--Teller (BET) analyses. The obtained XRD and EDX spectra confirmed crystallinity and elemental composition. The BET surface area of 30% cobalt-doped nickel oxide mixed with PC was estimated to be 17.67 m2 g-1, which is larger than that of 30% cobalt-doped nickel oxide, with a surface area of 11.05 m2 g-1. The electrode fabricated with 30% cobalt-doped nickel oxide showed better performance, and its electrochemical performance was further enhanced with the PC additive. The specific capacitance of the 30% cobalt-doped nickel oxide with PC additive reached 551 F g-1 at 0.1 A g-1 and 661 F g-1 at 5 mV s-1. The obtained results suggest that new-generation electrochemical electrodes can be optimized by adding PC during synthesis.
References
[1] S. Sharma & P. Chand, ``Supercapacitor and electrochemical techniques: a brief review'', Results in Chemistry 5 (2023) 100885. https://link.springer.com/article/10.1007/s10904-025-03861-x.
[2] A. Soam, R. Kumar, B. K. Singh & D. S. Saini, ``A comprehensive review on synthesis of nanocomposites for supercapacitor'', Journal of Inorganic and Organometallic Polymers and Materials 35 (2025) 9619. https://doi.org/10.1007/s10904-025-03861-x.
[3] A. T. Admase, E. D. Asrade & S. W. Fanta, ``A comprehensive review on energy storage materials & technologies: applications of nanofabrication techniques for enhanced performance and efficiency'', Materials for Renewable and Sustainable Energy 14 (2025) 56. https://doi.org/10.1007/s40243-025-00329-3.
[4] U. Ulissi & R. Raccichini, ``Past, present, and future of electrochemical energy storage: a brief perspective'', Frontiers of Nanoscience 19 (2021) 1. https://doi.org/10.1016/B978-0-12-821434-3.00013-2.
[5] G. Z. Chen, ``Linear and non-linear pseudocapacitances with or without diffusion control'', Progress in Natural Science: Materials International 31 (2021) 792. https://doi.org/10.1016/j.pnsc.2021.10.011.
[6] S. Pay'a, M. D. Casal, N. D'iez & M. Sevilla, ``A single route for the production of battery-type and capacitor-type electrode materials'', Carbon 235 (2025) 120056. https://doi.org/10.1016/j.carbon.2025.120056.
[7] B. Raut, M. Ahmed, H. Kim, M. K. Rahman, G. Bao, M. Islam & K. Nam, ``Battery-type transition metal oxides in hybrid supercapacitors: synthesis and applications'', Batteries 11 (2025) 60. https://doi.org/10.3390/batteries11020060.
[8] B. Guo, Y. Gao, Y. Li, K. Liu, X. Lv, C. Mi, L. Liu & M. Li, ``Battery-type-behavior-retention Ni(OH)$_2$--rGO composite for an ultrahigh-specific-capacity asymmetric electrochemical capacitor electrode'', ACS Omega 8 (2023) 6289. https://doi.org/10.1021/acsomega.2c06207.
[9] F. Yu, T. Huang, P. Zhang, Y. Tao, F. Cui, Q. Xie, S. Yao & F. Wang, ``Design and synthesis of electrode materials with both battery-type and capacitive charge storage'', Energy Storage Materials 22 (2019) 235. https://doi.org/10.1016/j.ensm.2019.07.023.
[10] R. M. Obodo, S. Mbam, H. Nsude, M. Ramzan, S. Ezike, I. Ahmad, M. Maaza & F. Ezema, ``Graphene oxide enhanced Co$_3$O$_4$/NiO composite electrodes for supercapacitive devices applications'', Applied Surface Science Advances 9 (2022) 100254. https://doi.org/10.1016/j.apsadv.2022.100254.
[11] F. Sultan, J. Zhu, D. I. Medina, P. P. Pescarmona, J. L. Cholula-D'iaz & D. M. Morales, ``Nickel cobalt oxide-based heterostructures as electrocatalysts for the oxygen evolution reaction at industry-relevant conditions'', International Journal of Hydrogen Energy 114 (2025) 440. https://doi.org/10.1016/j.ijhydene.2025.02.449.
[12] N. Ahamed, J. Pattar, R. Murthy, M. Kumar, V. Bhoomika, N. Raghavendra & C. Ravikumar, ``Electrochemical studies of nickel oxide nanoparticles via solution combustion method using green and chemical fuels'', Sustainable Chemistry for the Environment 5 (2024) 100063. https://doi.org/10.1016/j.scenv.2024.100063.
[13] K. Lee, G. Pan, T. Yang, P. Shen, K. Pan, T. Tiong, A. Nikoloski & C. Huang, ``Hierarchical manganese-doped nickel--cobalt oxide electrodes with graphene for use as high-energy-density supercapacitors'', Surfaces 8 (2025) 43. https://doi.org/10.3390/surfaces8030043.
[14] M. Manikandan, E. Manikandan, V. Swetha, S. Kurpaa, S. Vijay & V. Kiruthika, ``Nickel-copper-cobalt mixed oxide electrode material for high performance asymmetric supercapacitor'', Scientific Reports 14 (2024) 10821. https://doi.org/10.1038/s41598-024-61625-y.
[15] H. Xu, Y. Cao, Y. Li, P. Cao, D. Liu, Y. Zhang & Q. Li, ``High-loading Co-doped NiO nanosheets on carbon-welded carbon nanotube framework enabling rapid charge kinetic for enhanced supercapacitor performance'', Journal of Energy Chemistry 50 (2020) 240. https://doi.org/10.1016/j.jechem.2020.03.023.
[16] T. K. S. Fayaz, H. K. Chanduluru, R. H. Obaydo & P. Sanphui, ``Propylene carbonate as an ecofriendly solvent: stability studies of ripretinib in RPHPLC and sustainable evaluation using advanced tools'', Sustainable Chemistry and Pharmacy 37 (2024) 101355. https://doi.org/10.1016/j.scp.2023.101355.
[17] M. Rafiee, D. J. Abrams, L. Cardinale, Z. Goss, A. Romero-Arenas & S. S. Stahl, ``Cyclic voltammetry and chronoamperometry: mechanistic tools for organic electrosynthesis'', Chemical Society Reviews 53 (2024) 566. https://doi.org/10.1039/d2cs00706a.
[18] D. P. Mali, R. T. Patil, A. S. Patil & V. J. Fulari, ``Facile synthesis of NiO nanoflakes via hydrothermal route: effect of urea concentration'', Chemical Physics Letters 770 (2021) 138431. https://doi.org/10.1016/j.cplett.2021.138431.
[19] N. A. Mala, M. A. Dar, S. Sivakumar, K. S. Bhat, G. N. Sinha & K. M. Batoo, ``Electrochemical supremacy of cobalt-doped nickel oxide and its supercapacitor applications with its mesoporous morphology'', Journal of Materials Science: Materials in Electronics 33 (2022) 11582. https://doi.org/10.1007/s10854-022-08130-y.
[20] M. R. Islam, M. Rahaman, M. M. Billah & M. R. Islam, ``Hydrothermal synthesis of an MoS$_2$/MnO$_2$ nanocomposite: a unique 3D-nanoflower/1D-nanorod structure for high-performance energy storage applications'', Materials Advances 5 (2024) 5307. https://doi.org/10.1039/d4ma00065j.
[21] A. Temam, S. Getaneh, A. Alshoaibi, C. Awada, A. Nwanya, F. Ezema & P. Ejikeme, ``Effect of synthesis method on electrochemical activities of V$_2$O$_5$ nanoparticles for supercapacitor application'', Journal of Materials Science: Materials in Electronics 36 (2025) 763. https://doi.org/10.1007/s10854-025-14816-w.
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Copyright (c) 2026 Uba Nwankwo, Raphael Mmaduka Obodo, Precious Nkechinyere Kalu, Chinedum Obed Dike, John Elom Ekpe, John Ubi Arikpo, Kasi Ramesh, Subramaniam Ramesh, Fabian Ifeanyichukwu Ezema
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