Mechanistic investigation of defect-engineered, non-stoichiometric, and Morphology-regulated hierarchical rhombus-/spindle-/peanut-like ZnCo2O4 microstructures and their applications toward high-performance supercapacitors

• Published in: Applied surface science Vol. 529; p. 147123
• Main Authors: Reddy, G. Rajasekhara, Dillip, G.R., Sreekanth, T.V.M., Rajavaram, Ramaraghavulu, Raju, B. Deva Prasad, Nagajyothi, P.C., Shim, J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2020
• Subjects: Hierarchical ZnCo2O4 microstructures; Non-stoichiometry; Solvothermal method; Supercapacitors; X-ray photoelectron spectroscopy; Supercapacitors; Hierarchical ZnCo2O4 microstructures; Non-stoichiometry; Solvothermal method; X-ray photoelectron spectroscopy
• DOI: 10.1016/j.apsusc.2020.147123
• ISSN: 0169-4332

Formation Mechanism of Rhombus-, Spindle-, and Peanut-Like Self-Assemblies of Zinc Cobalt Oxide Microstructures were Engineered through Solvothermal Synthesis Method. And Their Non-Stoichiometric such as Cation-Deficient (Zn ions)/Excess (Co ions)-Dependent Enhanced Specific Capacitance was Examined for Supercapacitors. [Display omitted] •Self-assembled hierarchical rhombus-, spindle-, and peanut-like ZnCo2O4 microstructures were engineered.•A mechanistic study of the precursor concentration-dependent ZCO was studied.•Cation defect-mediated (Zn/Co ions) electrochemical performance of the ZCO was examined.•Peanut-like ZCO has a high surface area 70.04 m2 g−1 and a specific capacitance of 1608.95F g−1 at 0.35 A g−1. Self-assembled hierarchical rhombus-, spindle-, and peanut-like zinc cobaltite (ZnCo2O4, ZCO) microstructures have strategically engineered using an effective solvothermal approach. The various morphology-regulated ZCO samples have obtained by altering the concentration of precursors in the solvent. Effective strategic methods led to various regulated morphologies, as well as different physicochemical properties, such as the surface area/pore size/volume, crystalline nature, and non-stoichiometry of Zn and Co in the ZCO samples. The metal (Zn/Co)/O deficiencies have quantitatively estimated via X-ray photoelectron spectroscopy and confirmed by the Rietveld refinement of ZCO samples using X-ray diffraction data. A mechanistic study has performed to investigate the formation mechanism of the precursor concentration-dependent self-assembled ZCO microstructures. We demonstrate that the specific capacitance of ZCO has proportional to the Zn-deficiency/Co-excess. The Co-deficient-dependent electrochemical properties have studied for three samples and a decline in the following order: P-ZCO (1608.95 F g−1 at 0.35 A g−1) > S-ZCO (1007.48 F g−1 at 0.35 A g−1) > R-ZCO (629.05 F g−1 at 0.35 A g−1). The simple and inexpensive method of synthesized non-stoichiometric ternary metal oxides micro/nanostructures will introduce new directions in this emerging energy field.