Project description
Zinc batteries electrolyte design cut hydrogen gas and costs
Aqueous zinc ion batteries (AZIBs) are promising for large-scale energy storage due to their safety, affordability, and high ionic conductivity. Rechargeable anode-free zinc ion batteries (AFZIBs) offer enhanced energy density by eliminating the bulky zinc metal anode, but they face challenges like hydrogen gas evolution during cycling. This arises because the interaction between water and zinc ions weakens water’s O-H bonds, leading to hydrogen release. With the support of the Marie Skłodowska-Curie Actions programme, the WIZBAT project proposes a solution: localised water-in-salt electrolytes (LWiSEs), which use an inert solvent to reduce salt concentration. This approach aims to eliminate the interaction between water and zinc ion with low salt concentration to balance cost and efficiency.
Objective
Aqueous zinc ion batteries (AZIBs) have attracted tremendous attention for the application in the field of large-scale energy storage devices due to their instinct properties of non-flammability, low-cost and high ionic conductivity of aqueous electrolyte. Rechargeable anode-free zinc ion batteries (AFZIBs) have multiple advantages over its conventional counterpart, especially by removing Zn metal in its initial state, the weight and volume of anode-free cells is significantly reduced, maximizing the energy density of AZIBs. The obstacles impeding practical applications of AFZIBs originated from the H2 evolution during batteries cycling. In a typical zinc-ion battery electrolyte, Zn2+ solvated with six water molecules forms hydrated zinc ion [Zn(H2O)6]2+. Preliminary research implies that H2 evolution primarily originates from solvated water, rather than free water not interacting with Zn2+, since the interaction between H2O and Zn2+ weakens the O-H bond of H2O, leading to deprotonation of the solvated water. Water-in-salt electrolytes (WiSEs) can prevent the formation of hydrated zinc ions ([Zn(H2O)6]2+), thus, suppressing H2 evolution. However, in such case, boosted electrochemical performance is achieved only at high costs because a large quantity of expensive fluorinated salts is used in electrolyte. In this project, we aim to lower the WiSE salt concentration by diluting the electrolytes with an inert solvent (called a diluent) that dissolves the water but not the salt. Therefore, the diluent does not alter the salt solvation structure of WiEs, forming a localized water-in-salt electrolyte (LWiSE). The as-designed LWiSE is expected to have the same effect as WiSE regarding H2 evolution suppression but is comparable to the conventional dilute aqueous electrolyte in terms of production cost and eco-friendliness. The as-designed LWiSE will be finally demonstrated in different prototypes, from lab-scale coin cells to industry large-scale pouch cells.
Fields of science
Programme(s)
- HORIZON.1.2 - Marie Skłodowska-Curie Actions (MSCA) Main Programme
Funding Scheme
HORIZON-TMA-MSCA-PF-EF - HORIZON TMA MSCA Postdoctoral Fellowships - European FellowshipsCoordinator
76131 Karlsruhe
Germany