age,” he explains. And compared with
other alkalis, such as potassium or sodium,
lithium has the smallest ion size—and
third-lowest atomic weight on the periodic
table—meaning more electrons and charge
for a given batter y size. The energ y densit y
of lithium-ion cells is as much as four times
greater than that of the nickel-cadmium
batteries they’ve largely replaced.
Current lithium-ion batteries use a
liquid electrolyte where ions f low back
and forth between the anode and cathode,
recharging and discharging electrons.
The cathode (positive electrode) is a lith-
ium compound, and the anode (negative
electrode)—which determines total stor-
age—is made of graphite. This material is▲
Tw o S o l i d
Power
engineers
huddle at the
cell stacker
machine.“We could
reset our
expectations
for battery
life. It could
be as long as
25 years or
even half
a centur y.”
January/February 2022 43COURTESY SOLID POWER (THIS PAGE AND PREVIOUS SPREAD)