Presentation Title

ELECTROCHEMICAL DEPOSITION OF MANGANESE OXIDE FOR HYBRID-SUPERCAPACITORS

Start Date

November 2016

End Date

November 2016

Location

Watkins 1111

Type of Presentation

Oral Talk

Abstract

Supercapacitors can be used as a means of energy storage when fast charge and discharge is necessary. This means that while they have lower energy density than batteries, they have a much higher power density. Typical supercapacitors rely on an ionic double layer to store energy in the form of an electric field; however, researchers have found that their energy densities can be further boosted by introducing materials that undergo very fast redox reactions during charge and discharge. This phenomenon is known as pseudocapacitance, and the resulting device is known as a hybrid-capacitor. Manganese (IV) oxide, MnO2, has been researched at length as a pseudocapacitive material due to its relative safety, low cost, and high theoretical capacitance of approximately 1370 F∙g-1­. Because the pseudocapacitive reaction only occurs at the surface of the MnO2, thin layers of MnO2 are generally required to achieve high specific capacitance. Our focus is on electrochemically depositing thin layers of MnO2 onto different substrates in order to create electrodes for hybrid-supercapacitors. Aqueous KMnO4 was electrochemically reduced into MnO2 on stainless steel mesh (SSM) and activated carbon (AC) substrates. MnO2 deposits on SSM showed capacitances of over 200 F∙g-1­, higher than several reported literature values. Working, symmetrical supercapacitor cells were also built using the SSM electrodes and displayed specific capacitance values of over 25 F∙g-1. Characterization of MnO2 deposits on AC indicate that the deposits most likely filled the carbon’s porous structure, dramatically reducing the surface area of the carbon and yielding poor capacitance values.

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Nov 12th, 10:15 AM Nov 12th, 10:30 AM

ELECTROCHEMICAL DEPOSITION OF MANGANESE OXIDE FOR HYBRID-SUPERCAPACITORS

Watkins 1111

Supercapacitors can be used as a means of energy storage when fast charge and discharge is necessary. This means that while they have lower energy density than batteries, they have a much higher power density. Typical supercapacitors rely on an ionic double layer to store energy in the form of an electric field; however, researchers have found that their energy densities can be further boosted by introducing materials that undergo very fast redox reactions during charge and discharge. This phenomenon is known as pseudocapacitance, and the resulting device is known as a hybrid-capacitor. Manganese (IV) oxide, MnO2, has been researched at length as a pseudocapacitive material due to its relative safety, low cost, and high theoretical capacitance of approximately 1370 F∙g-1­. Because the pseudocapacitive reaction only occurs at the surface of the MnO2, thin layers of MnO2 are generally required to achieve high specific capacitance. Our focus is on electrochemically depositing thin layers of MnO2 onto different substrates in order to create electrodes for hybrid-supercapacitors. Aqueous KMnO4 was electrochemically reduced into MnO2 on stainless steel mesh (SSM) and activated carbon (AC) substrates. MnO2 deposits on SSM showed capacitances of over 200 F∙g-1­, higher than several reported literature values. Working, symmetrical supercapacitor cells were also built using the SSM electrodes and displayed specific capacitance values of over 25 F∙g-1. Characterization of MnO2 deposits on AC indicate that the deposits most likely filled the carbon’s porous structure, dramatically reducing the surface area of the carbon and yielding poor capacitance values.