Dissertation Defence: Material Design and Device Integration for Aqueous Zinc-ion Capacitors
September 11 at 9:30 am - 1:30 pm
Li Tao, supervised by Dr. Jian Liu, will defend their dissertation titled “Material Design and Device Integration for Aqueous Zinc-ion Capacitors” in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Mechanical Engineering.
An abstract for Li Tao’s dissertation is included below.
Examinations are open to all members of the campus community as well as the general public. This examination will be offered in hybrid format. Registration is not required to attend in person; however, please email jian.liu@ubc.ca to receive the Zoom link for this exam.
Abstract
Aqueous zinc-ion capacitors (AZICs) represent a promising alternative electrochemical energy storage solution to the current lithium-ion batteries (LIBs), particularly in fields that require high power and frequent fast charge/discharge cycles, such as power storage stations. Compared with LIBs, AZICs offer advantages in safety, cost, and environmental sustainability; however, their practical applications are hindered by limitations such as low-performance cathode materials, interface instability, and short-life electrolytes. This thesis developed high-energy and long-life AZICs by innovating and integrating carbon cathodes, aqueous electrolytes, and zinc anode modifications. First, this thesis developed a high-surface-area, mesopore-rich, and eco-friendly biomass-derived activated carbon (AC) as a cathode material. Secondly, a high-mass-loading AC cathode was fabricated to increase energy density and mechanical durability, and to gain a deep understanding of the relationship between the free-standing cathode fabrication process and its electrochemical performance in AZICs. Thirdly, to address the instability of the zinc metal anode, an ultrathin protective coating (ZnPON) was deposited using the plasma-enhanced atomic layer deposition technique to suppress zinc anode dendrite growth and side reactions. Lastly, urea-modified aqueous electrolytes were formulated to enhance the stability of the electrode/electrolyte interface and extend cycle life. Eventually, pouch cells (~4 cm width, ~5 cm length) and commercial-standard AA cylindrical cells (~1.45 cm diameter, ~5 cm length) were fabricated to demonstrate the potential of integrating research modifications into practical formats. By integrating material synthesis, electrode fabrication engineering, and interfacial modifications, this thesis seeks to narrow the gap between AZICs and practical applications.
