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

Abstract

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.

Heterogeneous Catalyst-Modified Anode in Solid Oxide Fuel Cells for Simultaneous Ammonia Synthesis and Energy Conversion

“…The presence of Mn 0 in H-Mn x N y was also confirmed using the WPPF analysis of the XRD patterns. Additionally, a broad and distinct peak P3 at 645.5 eV was observed in the Mn 2p spectra of Mn x N y , H-Mn x N y , and N-Mn x N y , which was attributed to the satellite peak of MnO and has been previously reported in a Mn 3 O 4 @N-doped carbon compound . This peak shifts toward lower BEs upon reduction and nitrification, proving oxide vacancy formation and nitrogen absorption into the vacancy during cell operation.…”

Boron Carbide as an Electrode Material: Tailoring Particle Morphology to Control Capacitive Behaviour

“…Moreover, the safety issues of batteries and extended cycle lives (>10 5 cycles) of SCs makes the latter more reliable for wearable and portable electronics [ 3 , 4 , 5 , 6 , 7 , 8 ]. Nevertheless, the relatively lower energy density of SCs prevents their widespread application [ 9 ].…”

Study on Electrochemical Performance of MnO@rGO/Carbon Fabric-Based Wearable Supercapacitors

“…Among all the metal oxides, manganese oxides (e.g., MnO, MnO 2 , and Mn 3 O 4 ) exhibit excellent electrochemical activity owing to their broad potential window [ 21 , 22 ]. Compared to the widely reported MnO 2 [ 23 , 24 , 25 ], manganese monoxide (MnO) has received less research attention, but has been one of the most promising active materials for electrochemical capacitors due to a high theoretical specific capacitance of ~1350 F g −1 , which is larger than that of MnO 2 (1110 F g −1 ) [ 26 , 27 ].…”