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Investigation and Development of Li-air and Li-air Flow Batteries

Title: Investigation and Development of Li-air and Li-air Flow Batteries.
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Name(s): Chen, Xujie, author
Zheng, Jianping P., professor directing dissertation
Liu, Tao, 1969-, university representative
Moss, Pedro L., committee member
Andrei, Petru, committee member
Florida State University, degree granting institution
College of Engineering, degree granting college
Department of Electrical and Computer Engineering, degree granting department
Type of Resource: text
Genre: Text
Issuance: monographic
Date Issued: 2014
Publisher: Florida State University
Place of Publication: Tallahassee, Florida
Physical Form: computer
online resource
Extent: 1 online resource (60 pages)
Language(s): English
Abstract/Description: This dissertation is mainly focused on the investigation of cathode in Li-air batteries using organic electrolyte and the development of high-rate rechargeable Li-air flow batteries. A Li-air battery using organic electrolyte with an air electrode made with a mixture of carbon nanotube (CNT) and carbon nanofiber (CNF) is utilized to investigate the capacity limitation effects of cathode using a multiple-discharge method. Scanning electron microscopy (SEM) images show that the discharge product mainly forms at the air side of cathode due to low oxygen solubility and diffusivity in the organic electrolyte. This inhomogeneous distribution of discharge product indicates that the Li-air cell falls short of the maximum capacity of air electrode. Electrochemical impedance spectra (EIS) demonstrated that during discharge at high current density (1 mA/cm2) pore blocking is the major factor that limits capacity; however, during discharge at low current density (0.2 mA/cm2) both pore blocking and impedance rise contribute to the capacity limitation. It's been confirmed that cathode is the dominant limitation to the discharge capacity. Also, the gradient porosity structure of cathode is able to increase the capacity based on the weight of carbon, but the electrolyte loading needs to be optimized to achieve high energy density of cell. A novel rechargeable Li-air flow battery is demonstrated. It consists of a lithium-ion conducting glass-ceramic membrane sandwiched by a Li-metal anode in organic electrolyte and a carbon nanofoam cathode through which oxygen-saturated aqueous electrolyte flows. It features a flow cell design in which aqueous electrolyte is bubbled with compressed air, and is continuously circulated between the cell and a storage reservoir to supply sufficient oxygen for high power output. It shows high rate capability (5 mA/cm²) and renders a power density of 7.64 mW/cm² at a constant discharge current density of 4 mA/cm². Adding RuO² as a catalyst in the cathode, the battery showed a high round-trip efficiency (ca. 83%), with the overpotentials of 0.67 V between charge and discharge at a current of 1 mA/cm². A Li-air flow battery using graphite as anode is also demonstrated for several cycles.
Identifier: FSU_migr_etd-9156 (IID)
Submitted Note: A Dissertation submitted to the Department of Electrical and Computer Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
Degree Awarded: Fall Semester, 2014.
Date of Defense: October 10, 2014.
Keywords: Li-air battery, Li-air flow battery
Bibliography Note: Includes bibliographical references.
Advisory Committee: Jim P. Zheng, Professor Directing Dissertation; Tao Liu, University Representative; Pedro Moss, Committee Member; Petru Andrei, Committee Member.
Subject(s): Electrical engineering
Force and energy
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_migr_etd-9156
Owner Institution: FSU

Choose the citation style.
Chen, X. (2014). Investigation and Development of Li-air and Li-air Flow Batteries. Retrieved from http://purl.flvc.org/fsu/fd/FSU_migr_etd-9156