Mathematical Modeling of Electrochemical Capacitors

Open Access
Author:
Hasyim, Muhammad Risyad
Area of Honors:
Chemical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Ramakrishnan Rajagopalan, Thesis Supervisor
  • Andrew Zydney, Honors Advisor
Keywords:
  • Electrochemistry
  • Chemical Engineering
  • Mathematical Modeling
  • Impedance Spectroscopy
  • Electric Double-Layer Capacitor
  • Pseudocapacitor
Abstract:
Electrochemical capacitors have received considerable interest as energy-storage solutions to many areas in engineering. To bridge the gap between experimental investigations of electrochemical capacitors and the mathematical modeling of these devices, a first-principles modeling method named Frequency-Domain Admittance Method (FDAM) was developed to analyze and quantitatively predict performance characteristics of electrochemical capacitors. FDAM allows frequency-domain electrical data obtained through impedance spectroscopy to be used for quantitative predictions of a device's discharge characteristics, capacitance, specific energy, and power. Electrical double layer capacitors (EDLCs) and pseudocapacitors were the two types of electrochemical capacitors investigated in this work. Suitable models that address device, macroscopic, and microscopic level description of each capacitor were developed along with numerical methods that allow the implementation of FDAM. Results have shown remarkable accuracy for different case studies of EDLCs but a deviation in the pseudocapacitor single case study. Theoretical and numerical studies on each derived model show the capability of FDAM in holistically observing the effects of device architecture and microscopic charge-storage mechanism.