Organic Crosslinked Polymer-Derived N/O-Doped Porous Carbons for High-Performance Supercapacitor

Nanostructured Electrodes for High-Performance Supercapacitors and Batteries

Emerging renewable energy sources have received extensive attention in the past few decades [...].

Deep Eutectic Solvent for Facile Synthesis of Mn3O4@N-Doped Carbon for Aqueous Multivalent-Based Supercapacitors: New Concept for Increasing Capacitance and Operating Voltage

The capacitance and operating voltage of supercapacitors as well as their energy density have been increased by development of different materials and electrolytes. In this paper, two strategies, for the first time, were used to improve energy density: Mn₃O₄- and N-dual doped carbon electrode and aqueous mixture of multivalent ions as electrolyte. Mn₃O₄- and N-dual doped carbon was prepared by a novel and cost-effective procedure using deep eutectic solvent. XRD, XPS, and FTIR confirmed presence of Mn₃O₄ and nitrogen, while SEM and EDS elemental mapping showed micrometer-sized nanosheets with uniform distribution of C, O, N, and Mn atoms. Charge storage behavior of carbon was tested in aqueous multivalent-based electrolytes and their mixture (Ca²⁺-Al³⁺). Regarding both specific capacitance and workable voltage, the Ca²⁺-Al³⁺ mixed electrolyte was found as the best optimal solution. The calcium addition to the Al-electrolyte allows the higher operating voltage than in the case of individual Al(NO₃)₃ electrolyte while the addition of Al³⁺ ion in the Ca(NO₃)₂ electrolyte improves the multivalent-ion charge storage ability of carbon. As a result, the specific energy density of two-electrode Mn₃O₄@N-doped carbon//Al(NO₃)₂+Ca(NO₃)₂//Mn₃O₄@N-doped carbon supercapacitor (34 Wh kg^-1 at 0.1 A g^-1) overpasses the reported values obtained for Mn-based carbon supercapacitors using conventional aqueous electrolytes.

Momordica Grosvenori Shell-Derived Porous Carbon Materials for High-Efficiency Symmetric Supercapacitors

Porous carbon materials derived from waste biomass have received broad interest in supercapacitor research due to their high specific surface area, good electrical conductivity, and excellent electrochemical performance. In this work, Momordica grosvenori shell-derived porous carbons (MGCs) were synthesized by high-temperature carbonization and subsequent activation by potassium hydroxide (KOH). As a supercapacitor electrode, the optimized MGCs-2 sample exhibits superior electrochemical performance. For example, a high specific capacitance of 367 F∙g^-1 is achieved at 0.5 A∙g^-1. Even at 20 A∙g^-1, more than 260 F∙g^-1 can be retained. Moreover, it also reveals favorable cycling stability (more than 96% of capacitance retention after 10,000 cycles at 5 A∙g^-1). These results demonstrate that porous carbon materials derived from Momordica grosvenori shells are one of the most promising electrode candidate materials for practical use in the fields of electrochemical energy storage and conversion.