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In this paper, the effects of nickel foam with different thicknesses, as a fluid collector, on the morphology and properties of electrode materials were explored. The Fe2O3 material, which is a common active material for supercapacitor electrodes, was used in combination with MgFe2O4. This combination resulted in better electrochemical performance and cycle stability for the Fe2O3 material. The synthesis ratio of Fe2O3/MgFe2O4 materials with the best stability, as reported in a previous article, was selected for this study. The electrode with the best performance was then selected and assembled with activated carbon to form an asymmetric supercapacitor. This supercapacitor exhibited a high specific capacity of 240 C/g, an energy density of 58.75 Wh/kg, and a power density of 200.4 W/kg at a current density of 1 A/g. These findings provide valuable references for the selection of different fluid collectors with electrodes. [ABSTRACT FROM AUTHOR]

The Fe 2 O 3 material is a common active material for supercapacitor electrodes and has received much attention due to its cheap and easy availability and high initial specific capacitance. In the present study, we prepared adhesive-free Fe 2 O 3 sheet electrodes for supercapacitors by growing Fe 2 O 3 material on nickel foam by hydrothermal method. The sheet electrode exhibited a high initial specific capacitance of 863 F g -1 , but we found that the sheet lost its specific capacitance too quickly through cyclic stability tests. To solve this problem, Fe 2 O 3 /MgFe 2 O 4 composites were grown on nickel foam (NF). It was found through testing that the cycling stability of the sheet electrode gradually increased as the content of MgFe 2 O 4 material increased. When the molar ratio of Fe 2 O 3 to MgFe 2 O 4 material was 1 : 1, the initial specific capacitance of the sheet electrode was 815 F g -1 and the capacitance remained at 81.25% of the initial specific capacitance after 1000 cycles. The better cycling stability results from the more stable structure of the composite, the synergistic effect leading to better reversibility of the reaction., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

In this paper, LaCoO 3 powders were prepared by the urea combustion method and used as electrode materials for supercapacitors. The effect of the potential window and the current density on the performance degradation of LaCoO 3 electrodes during the cycling test was analyzed. The degradation mechanism of LaCoO 3 -based symmetric supercapacitors was discussed. The results of the cycling test show that: with the increase in potential window and current density, the performance degradation in the cycling test becomes more intense. The results of cyclic voltammetry tests, galvanostatic charge-discharge tests, X-ray photoelectron spectroscopy tests and KOH electrolyte concentration measurements before and after the cycling test show that the degradation of the supercapacitors is mainly caused by the occurrence and accumulation of irreversible redox reactions during the charge and discharge process, which reduces the ratio of Co 2+ /Co 3+ and the number of oxygen vacancies., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)