Doctor of Philosophy
Institute for Superconducting and Electronic Materials
Owing to the high capacity of metallic Zn anode and intrinsically safe aqueous electrolyte, aqueous Zn-ion batteries (AZIBs) have become advanced energy storage alternatives beyond the lithium-ion batteries by providing cost benefit, high safety, and competitive energy density. There has been a new wave of research interest across AZIBs, however, the state-of-the-art AZIBs are still far from satisfactory. One important reason is that Zn anode still suffers from low Coulombic efficiency (CE) and inferior cycling stability, due to its notorious dendrite formation and side reactions (e.g. corrosion, passivation, and H2 evolution) in aqueous electrolytes. Accordingly, my doctoral project is focused on improving the electrochemical performance of AZIBs via enabling highly stable and reversible Zn metal anode, including three subprojects (1) in situ construction of highly Zn2+-conductive solid electrolyte interphase for stable Zn anode; (2) an in situ polymeric interface on Zn anode towards high-performance aqueous Zn-ion batteries; (3) boosting advanced aqueous Zn/MnO2 batteries via electrolyte salt chemistry.
In the first subproject, an in-situ formation of a dense, stable, and highly Zn2+- conductive SEI layer (hopeite) was demonstrated in aqueous Zn chemistry, by introducing Zn(H2PO4)2 salt into the electrolyte. The hopeite SEI enables uniform and rapid Zn-ion transport kinetics for dendrite-free Zn deposition, and restrains the side reactions via isolating active Zn from the bulk electrolyte. Under practical testing conditions with an ultrathin Zn anode, a low negative/positive capacity ratio, and lean electrolyte, the Zn/V2O5 full cell retained 94.4 % of its original capacity after 500 cycles. This work provides a simple yet practical solution to high-performance aqueous battery technology via building in-situ SEI layers.
Zeng, Xiaohui, Stable Zinc Metal Anode for High-performance Aqueous Zn-ion Batteries, Doctor of Philosophy thesis, Institute for Superconducting and Electronic Materials, University of Wollongong, 2022. https://ro.uow.edu.au/theses1/1401
FoR codes (2008)
0912 MATERIALS ENGINEERING
Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.