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“It’s lot like growing food in rate, like that of batteries in separator, placed between the
your garden in the spring, most cars or laptops, would anode and the cathode. Most
putting the extra in a container hamper a grid battery higher-temperature molten-salt
in your freezer, and then designed to store energy for batteries require a ceramic
thawing it out for dinner in months. Notably, the PNNL separator, which can be more
the winter”. said first author freeze- thaw battery has expensive to make and
Minyuan Miller Li. retained 92 percent of its susceptible to breakage
capacity over 12 weeks. during the freeze- thaw cycle.
The battery is first charged by
heating it up to 180 degrees In other words, the energy The PNNL battery uses
Celsius, allowing ions to flow doesn’t degrade much; it’s simple fiberglass, possible
through the liquid electrolyte to preserved, just like food in a because of the battery’s stable
create chemical energy. Then, freezer. chemistry. This cuts costs and
the battery is cooled to room makes the battery sturdier
temperature, essentially locking Ordinary ingredients a when undergoing freeze-thaw
in the battery’s energy. The plus: cycles.
electrolyte becomes solid and
the ions that shuttle energy The team avoided rare, expensive ‘Reducing battery costs is critical.
stay nearly still. When the and highly reactive materials. That is why we’ve chosen
energy is needed, the battery Instead, the aluminum-nickel common, less-expensive
is reheated and the energy molten- salt battery is chock materials to work with, and
flows. full of Earth-abundant, why we focused on removing
common materials. The the ceramic separator, said
The freeze-thaw phenomenon anode and cathode are corresponding author
is possible because the solid plates of aluminum Guosheng Li, who led the
battery’s electrolyte is molten and nickel, respectively. study. The battery’s energy is
salt -a molecular cousin of They’re immersed in a sea of stored at a materials cost of
ordinary table salt. The material molten-salt electrolyte that is about $23 per kilowatt hour,
is liquid at higher temperatures solid at room temperature but measured before a recent jump
but solid at room flows as a liquid when heated. in the cost of nickel. The team is
temperature. The team added sulfur -another exploring the use of iron, which
common, low- cost element - to is less expensive, in hopes of
The freeze-thaw concept the electrolyte to enhance the bringing the materials cost
dodges a problem familiar to battery’s energy capacity. down to around $6 per kilo-
anyone who has let their car watt hour, roughly 15 times
sit unused for too long: a One of the biggest advantages less than the materials cost
battery that self-discharges as of the battery is the composition of today’s lithium-ion
it sits idle. A fast discharge of a component, called a batteries.
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