A review of recent advances in manganese-based supercapacitors

Engineering Oxygen Vacancies on Mixed-Valent Mesoporous α-MnO2 for High-Performance Asymmetric Supercapacitors

“…The highly desired green and efficient energy utilization accelerates the progress of energy storage techniques. − Supercapacitors (SCs) have received tremendous attention because of their high power density and good cycle stability. − A major challenge of SCs is to enhance their energy density to meet the high-energy density ( E ) battery applications in the future. − Based on the equation of E = 1/2 CV 2 , the energy density of SCs can be elevated by broadening the voltage window ( V ) and improving the specific capacitance ( C ). − Numerous research studies have focused on developing asymmetric SCs (ASCs) that can utilize different operating voltages of negative and positive electrodes, thereby increasing the potential window of the cell system. − Most of the ASCs are composed of two reactions: one for electric double-layer reaction which possesses a carbon-based material as the negative electrode material and another for pseudocapacitance reaction with metal oxides as the positive electrode material. ,, The transition-metal oxide as a material of pseudocapacitance is the main strategy for efficient SCs because of the limitated specific capacitance of activated carbon (AC) (usually less than 300 F g –1 ). − Mesoporous α-MnO 2 , with a high theoretical capacity (∼1370 F g –1 ), is considered as a potential alternative to the electrode material of commercial RuO 2 because of its prominent 2 × 2 open tunnel structure (about 0.46 nm). − However, the poor electrical conductivity and relatively sluggish ion-transfer performance of α-MnO 2 hinder the high energy density and large-scale applications seriously because the internal electronic configuration of α-MnO 2 limited external conductive reinforcement …”

MoO3–Carbon Nanotube Negative Electrode Designed for a Fully Hybrid Asymmetric Metal Oxide-Based Pseudocapacitor Operating in an Organic Electrolyte

“…As part of the composite material, they will increase electronic conductivity and allow good accessibility to the metal oxide surface . As a result, the MnO 2 -based electrodes exhibit reversible redox activity in a potential window extending from 0 to 0.9 V vs Ag/AgCl in aqueous electrolytes. , …”

“…Finally, the major part of the works in the domain of MnO 2 or MoO 3 pseudocapacitors is based on very common aqueous electrolytes. ,, Pseudocapacitors working with high performances in an organic electrolyte are scarce. The two-electrode device that is presented in this paper has been developed in an organic electrolyte (0.5 M LiTFSI in GBL) to ensure a higher stability in terms of voltage and mechanical integrity, solving certain problems of water solubility of the negative material observed in a more classic aqueous electrolyte (MoO 3 with a water solubility of 1 g/L at 20 °C). , The energy densities, power densities, and cycling performances have been evaluated.…”

“…23 As a result, the MnO 2 -based electrodes exhibit reversible redox activity in a potential window extending from 0 to 0.9 V vs Ag/AgCl in aqueous electrolytes. 24,25 The objective of this work was to develop metal oxide/ carbon electrodes with a high loading of electroactive materials ensuring high capacitances and rapid storage kinetics, with the aim of increasing the energy density of supercapacitors while maintaining good power density, in order to make them competitive compared to certain batteries in specific applications. 10 We present in this contribution a new way of development of a high-capacitance MoO 3 -based nanostructured binder-free negative electrode using industrially suitable fabrication methods.…”

Highly graphitic porous carbon preparedviaK2FeO4-assisted KOH activation for supercapacitors

“…1,2 Supercapacitors are divided into electric doublelayer capacitors (EDLCs) and pseudocapacitive capacitors according to their storage mechanism. 3 The electrode materials utilized directly determine the energy density and power density of the supercapacitors, which include metal compounds, 4,5 conducting polymers 6,7 and carbon-based materials. 8,9 In general, carbon-based materials store charge based on the EDLCs storage mechanism.…”