- The battery can be cycled in a stable manner with high coulombic efficiency and a volumetric capacity
- For the anode, the researchers used niobium tungsten oxide
According to a report by Greencarcongress, a team of engineers at Rensselaer Polytechnic Institute have demostrated that by using aqueous electrolytes instead of the typical organic electrolytes, a significantly safer and cost-efficient battery can be developed. A paper on their work is published in the journal Energy Storage Materials.
As per the report, the battery the team developed can be cycled in a stable manner with high coulombic efficiency and a volumetric capacity. The report also said that the battery could be cycled at high rates which increased the charge/discharge rate by an order of magnitude (0.5C–5C). This resulted in about 25 per cent reduction in capacity
Niobium tungsten oxide as anode
The report said that aqueous electrolytes are non-flammable and are not sensitive to moisture in the manufacturing process. This makes them easier to work with and make them less expensive. It also generates the challenge of maintaining performance.
The team used a special type of aqueous electrolyte known as a water-in-salt electrolyte (lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) aqueous solution). This solution is less likely to electrolize as per the report. For the cathode, the researchers used lithium manganese oxide and for the anode, they used niobium tungsten oxide. This complex oxide has not been explored in an aqueous battery before as per the report.
Diffuse quickly
The report said that Niobium tungsten oxide is relatively heavy and dense. This weight makes its energy storage based on mass about average. The dense-making in the electrode makes it possible to store energy based on volume in a good amount. The crystal structure of this material also has well-defined channels that allows lithium ions to diffuse quickly. This makes charging faster as per the report.
Practical implications
According to the report, achieving this kind performance along with a low cost and improved safety will have practical implications. For applications like portable electronics, electric vehicles, and grid storage, the capability to pack the maximum amount of energy into a limited volume is very crucial.
