Battery technology under development at MIT could someday make recharging batteries as quick and easy as a trip to the gas station.
Known as semi-solid flow cells, the new battery design turns the chemistry of traditional lithium-ion batteries into quicksand-like tiny particles. The resultant slime — which researchers jokingly call “Cambridge crude” — has an extremely high energy density and is cheaper to manufacture than the innards of a traditional lithium-ion battery. The researchers claim battery cost and size could be cut in half as a result.
The new design should make it possible to reduce the size and the cost of a complete battery system, including all of its structural support and connectors, to about half the current levels. That dramatic reduction could be the key to making electric vehicles fully competitive with conventional gas- or diesel-powered vehicles, the researchers say.
Another potential advantage is that in vehicle applications, such a system would permit the possibility of simply “refueling” the battery by pumping out the liquid slurry and pumping in a fresh, fully charged replacement, or by swapping out the tanks like tires at a pit stop, while still preserving the option of simply recharging the existing material when time permits.
In addition to potential applications in vehicles, the new battery system could be scaled up to very large sizes at low cost. This would make it particularly well-suited for large-scale electricity storage for utilities, potentially making intermittent, unpredictable sources such as wind and solar energy practical for powering the electric grid.
The research, which was originally published in the Wiley journal Advanced Energy Materials, was able to overcome the low energy density of liquid-flow batteries by creating a semi-solid material that “kind of oozes,” according to Chiang. The new material is able to store energy in “suspensions of solid storage compounds” and the “charge transfer is accomplished via dilute yet percolating networks of nanoscale conductors.”
The result is that the cathodes and anodes of the battery are particles that are suspended in the liquid electrolyte. And the two different suspensions are pumped through systems separated by a thin porous membrane.
The design also separates the storing and discharging of the battery into two different physical structures. According to Chiang, this separated architecture will enable batteries to be designed more efficientl
Since the design is expected to reduce the size (and cost) of a battery system by as much as half, it is being touted as a way to make electric vehicles more competitive with internal combustion engines.