Water-Soluble Redox Materials and Their Applications in Aqueous Batteries

Ever-increasing worldwide energy requirements and concerns on global warming have stimulated the development of renewable energy resources. However, intermittency of renewables is the biggest challenge for their widespread application. Advanced large-scale energy storage technologies are thus urgently demanded to effectively utilise these renewable energy resources and increase the stability and reliability of power generation. Batteries are considered as a promising energy storage system, which has been under intensive investigation for overcoming the current limitation of renewables. In the PhD research, due to the safety (using the non-combustible aqueous electrolytes) and cost-effectiveness (low-cost separators and aqueous electrolyte salts), aqueous batteries are focused in terms of electrocatalyst design for optimising the aqueous redox reaction, development of novel aqueous battery systems by exploring the existing electroactive materials in the new systems and by exploring new redox-active materials for achieving the high-performance aqueous batteries. Specifically, in the first project, hydrophilic tannic acid modified WS2 nanosheets are developed as polysulfide conversion electrocatalysts in alkaline aqueous solutions, which overcome the sluggish reaction kinetics of polysulfide and improve the electrocatalytic activity for polysulfide reactions in aqueous solution. This work opens the way to the preparation of optimal electrocatalysis of polysulfide redox reactivity and provides an alternative option to improve the aqueous polysulfide-based batteries. In the second project, a novel alkaline redox flow battery is studied by using methyl viologen (MV) as anolyte and potassium ferrocyanide as catholyte. MV is for the first time explored in the alkaline condition, which shows enhanced electrochemical kinetics compared to in the neutral system. This work demonstrates the potential of MV as the anode material candidate in the alkaline battery. In the third project, a non-persistent radical precursor, N-hydroxyphthalimide (NHPI), is reported for the first time as a low-cost, high-potential organic cathode with rapid kinetics in a semi-aqueous redox battery. A novel combined strategy is proposed in stabilising non-persistent radicals, which includes the binary electrolyte system, cluster-anchoring to polymer chains and cold quenching. This work offers a measure to access the high-potential and kinetic radical chemistry for high-voltage aqueous redox batteries.

Grantor dc:publisher

UNSW, Sydney

Year dc:date

2019

Author dc:creator

• Tian, Yuheng

• Aqueous polysulfide reaction
• Aqueous batteries
• Water-soluble redox materials
• Alkaline flow battery
• N-hydroxyphthalimide (NHPI)

Statement dc:rights

• open access
• CC BY-NC-ND 3.0
• free_to_read

Licence

• https://purl.org/coar/access_right/c_abf2
• https://creativecommons.org/licenses/by-nc-nd/3.0/au/

Language dc:language

EN

Identifier

https://doi.org/10.26190/unsworks/3941

OAI identifier oai:identifier

oai:unsworks.library.unsw.edu.au:1959.4/66867