Inside-outside OH- incursion involved in the fabrication of hierarchical nanoflake assembled three-dimensional flower-like α-Co(OH)2 for use in high-performance aqueous symmetric supercapacitor applications

Sajid Ali Ansari; Nazish Parveen; Mohd Al Saleh Al-Othoum; Mohammad Omaish Ansari

doi:10.1016/j.jare.2022.10.009

Inside-outside OH^- incursion involved in the fabrication of hierarchical nanoflake assembled three-dimensional flower-like α-Co(OH)₂ for use in high-performance aqueous symmetric supercapacitor applications

J Adv Res. 2023 Aug:50:107-116. doi: 10.1016/j.jare.2022.10.009. Epub 2022 Oct 21.

Authors

Sajid Ali Ansari¹, Nazish Parveen², Mohd Al Saleh Al-Othoum³, Mohammad Omaish Ansari⁴

Affiliations

¹ Department of Physics, College of Science, King Faisal University, P.O. Box 400, Hofuf, Al-Ahsa 31982, Saudi Arabia. Electronic address: sansari@kfu.edu.sa.
² Department of Chemistry, College of Science, King Faisal University, P.O. Box 380, Hofuf, Al-Ahsa 31982, Saudi Arabia. Electronic address: nislam@kfu.edu.sa.
³ Department of Physics, College of Science, King Faisal University, P.O. Box 400, Hofuf, Al-Ahsa 31982, Saudi Arabia. Electronic address: malothoum@kfu.edu.sa.
⁴ Center of Nanotechnology, King Abdulaziz University, Jeddah 21589, Saudi Arabia.

Abstract

Introduction: The energy industry has been challenged by the current high population and high energy consumption, forcing the development of effective and efficient supercapacitor devices. The crucial issues until now have been high production cost, deprived cyclic stability, and squat energy density. To resolve these problems, various approaches have been taken, such as the development of long-life electrode materials with high capacity, rapid charging, and slow discharging to overcome poor life cycle stability.

Objectives: In the present work we focus on fabricating cost-effective unique-morphology, high-surface-area alpha-Co(OH)₂ for application in an aqueous-electrolyte symmetric supercapacitor.

Methods: In this study, hierarchical nanoflakes assembled in three-dimensional (3D) flower-shaped cobalt hydroxide (HN-3DF-α-Co(OH)₂) electrode were synthesized using the solvothermal method with sodium dodecylbenzene sulfonate (SDBS) and methanol as solvents. Spectroscopic and microscopic techniques were used to characterize fabricated HN-3DF-Co(OH)₂, which revealed that the materials electrode exhibited the alpha phase with a hierarchical flower-like structure. A half-cell electrochemical assembly (three-electrode assemble cell) and symmetric full cell (two-electrode assemble cell) were examined in an aqueous electrolyte.

Results: In three-electrode assembly cells, HN-3DF-α-Co(OH)₂ exhibited 719.5 Fg^-1 specific capacitance (C_sp) at 1 Ag^-1 with excellent cyclic retention stability of approximately 88% after 3000 cycles. In two-electrode symmetric supercapacitive systems, HN-3DF-α-Co(OH)₂ achieved a maximum C_sp of 70.3 Fg^-1 at 0.4 Ag^-1 with the highest energy density of approximately 6.25 Wh/kg at a power density of 328.94 W/kg. The fabricated two-electrode assembly cell with the HN-3DF-α-Co(OH)₂ electrode retained cyclic stability of approximately 85% after 5000 repeated charge and discharge cycles.

Conclusion: Solvothermally-synthesized, optimized HN-3DF-α-Co(OH)₂ showed outstanding electrochemical performance results in three- and two-electrode systems. This unique aqueous symmetric supercapacitor can be used to design cost-effective symmetric capacitors based on metal hydroxide.

Keywords: 3D flower; Charge/discharge; Hierarchical; Supercapacitor; α-Co(OH)(2).