Flow battery is regarded as a promising option for prolonged grid-level energy storage, though an attainment of high efficiency in the past was often accompanied with an exorbitant level of cost due to the necessary utilization of the expensive vanadium as raw material. The Massachusetts Institute of Technology (MIT) has now managed to release an electrode formula for high-efficiency batteries that is more affordable, which is an ice-cream-like semi-solid flow battery.

Flow batteries are advantageous in grid-level energy storage systems pertaining to expansion flexibility in the quantity of establishment, as well as a much lower cost option compared to mass lithium-ion batteries. Vanadium redox battery is a common flow battery technology, and is formed with two electrolyzers that are separated by a proton exchange membrane, where vanadium would transform into various oxidation states, with no deterioration as well. By using flow batteries, a large quantity of renewable energy could be stored at a comparatively lower cost for months, which replenishes the void of intermittent energy such as solar and wind power.

Emre Gençer, a research scientist of MIT Energy Initiative, commented that semi-solid flow batteries may just rescue lives and properties, especially during natural disasters, where renewable energy such as solar and wind power systems are unable to generate power for one or more days.

(Source: MIT)

MIT has now proposed a more affordable flow battery design, which looks like a pile of peat composite from afar, and has a consistency to that of honey. The research team mixed manganese dioxide particles with the conductive additives inside the black goo, which formed a semi-solid flow battery that looks like ice-cream.

Despite being a semi-solid flow battery, which means that it requires additional power for liquid to pass through the proton exchange membrane, the research team at MIT believes that the new flow battery will still attain excellent performance in cost and efficiency. A calculation of capital cost after continuous operation of 8, 24, and 72 hours denotes a better cost level compared to vanadium redox batteries and lithium-ion batteries.

Thaneer Malai Narayanan, a research author of the MIT Department of Mechanical Engineering, commented that the research team had a better understanding of the battery’s performance and cost from a comprehensive bottom-up analysis, and implemented compromises accordingly, before finally proving that the new design is more affordable than other systems, with ability to flexibly expand scale of establishment.

This particular study does not negate the role of lithium-ion batteries in battery energy storage systems since these two technologies are responsible for supporting different grid conditions. The millisecond response mechanism of lithium batteries is able to effectively stabilize grid frequency, as well as elevate the quality and stability of power supply, and satisfy short-term power storage, while hydrogen fuel cells and flow batteries are able to replenish prolonged void in energy storage. The MIT research team plans to continue developing new battery systems, and their respective roles in power systems.

 (Cover photo source: Unsplash)