The innovation engine for new materials

Alexander Khechfe

Alexander Khechfe


University of California, Santa Barbara


Chemical Engineering

Site Abroad: 

Chalmers Institute of Technology, Gothenburg, Sweden


Simon Lindberg
Florian Nitze
Anders Palmqvist

Faculty Sponsor(s): 

Aleksander Matic

Faculty Sponsor's Department: 

Chemical Engineering
Chemistry and Biochemistry

Project Title: 


Project Description: 

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[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.