Dr. Valdés-Morales, Héctor

In this study, perovskite-structured lanthanum cobalt oxide(LaCoO3/LCO) systems with particle and flake morphologies were developed using sol−gel and hydrothermal methods, respectively, in order to investigate their morphological structure-dependent properties for potential supercapacitor applications. The structural analysis confirms that both methods yield LaCoO3with improved crystalline properties. The energy storage performance of the developed materials is studied in a three-electrode configuration using a 1 MKOH electrolyte. The results indicated superior electrochemical performance for the LCO nanoflakes, exhibiting specific capacitances of ∼215 F g−1 at a scan rate of 5 mV s−1 and ∼136 F g−1 at a current density of 1 A g−1. In comparison, the LCO nanoparticles showed ∼119 F g−1 at a scan rate of 5 mV s−1 and ∼99F g−1 at a current density of 1 A g−1. This difference can be largely attributed to their respective morphologies, porous structures, and surface defects. Further, the nanoflakes demonstrated an exceptional capacitance retention of ∼97% even after 5000 charge−discharge cycles. The findings of this study suggest that the properties of perovskite LaCoO3 can be tuned by adjusting its morphology through various synthesis methods, making LaCoO3 a viable and robust system for energy storage applications.

There is an enormous demand for energy storage applications with a high specific capacity, superior energy and power density, and long-life cycles because of the increase in portable electronic appliances. The use of ternary metal oxide electrode materials for energy storage applications in supercapacitors based on multi-redox sites has gained more attention from researchers due to their outstanding specific capacitance and numerous redox sites. Copper cobalt ferrites (CuCoFe2O4) nanoparticles (NPs) have been synthesised by the simple microwave combustion method and employed as a positive electrode material for energy storage in supercapacitors (SCs). To study the physical and electrochemical properties of the prepared nanoparticles by XRD, FTIR, SEM-EDX, HR-TEM, and electrochemical analysis have been carried out. X-ray diffraction planes indicating the cubic spinel structure with a space group of Fd-3m and the crystalline phase purity of the synthesised CuCoFe2O4 NPs were also characterized by Rietveld refinement. HR-TEM analysis of the existing agglomeration of particles and SAED pattern shows the excellent crystalline nature of the materials. The CuCoFe2O4 electrode obtained an outstanding specific capacitance of 237.5 F g−1 at 0.5 A g−1 current density in a 3 M KOH electrolyte in a standard three-electrode system. Further fabricated of a solid-state asymmetric supercapacitor (ASC) device by using CuCoFe2O4 NPs and activated carbon (AC) as the positive and negative electrodes, respectively. This ASC device offers a superior energy density value of 16 Wh kg−1 and a power density of 8048 W kg−1. In addition, the ASCs device exhibits cycle stability of 82 % after 10,000 GCD charge and discharge cycles at a current density of 40 A g−1, displaying its high cycling stability.