plentiful, conducts well, and is easy to work
with. However, lithium metal’s capacity is
10 times that of graphite.
“Lithium metal is the highest-capacity
material we know of,” says Jun Liu, Ph.D.,
a director at Pacific Northwest National
Laboratory in Richland, Washington.
There, Liu leads a consortium searching
for the electric-vehicle battery holy grail:
light, fast charging, and resistant to cor-
rosion. He believes they’ve found that in
recent lithium-metal advancements.
TO TAP LITHIUM’S potential, research-
ers have spent decades working through
the metal’s numerous roadblocks. Chief
among them, says Liu, is its reactivity.
“The difficulty is, lithium metal is too
reactive. You can think of it as corrosion—
if you get it in contact with anything, it
corrodes everything.”
The main form of lithium corrosion
in batteries are dendrites, which are
branched lithium structures that grow out
from the anode. Dendrites, which are also
a problem for lithium-ion batteries, can
puncture battery parts and short-circuit
the cell. In a traditional lithium-ion bat-
tery with a liquid electrolyte, that can lead
to a fire. The liquid electrolyte is a f lamma-
ble solvent just waiting to be ignited—it’s
the fuel behind the battery fires on air-
planes that have made recent headlines.
Scientists eventually landed on a
solution that prevented the growth of
dendrites and eliminated the risk of
fire: a solid electrolyte—often made of a
ceramic similar to a semiconductor—that
replaced the f lammable liquid electro-
lyte and physically blocked the growth of
dendrites. And if dendrites still manage
to push through the ceramic electrolyte,
there’s no f lammable reactivity.
Solid electrolytes present addi-
tional challenges. They must match
the relatively easy seal between a liquid
electrolyte and the cathode and anode—
the liquid simply forms around them.
Lithium is at least malleable at room
temperature and can be pressed into the
craggy surfaces of a material, but there's
still the connection to the cathode. And
▲
Dasgupta's
research
includes a
manufacturing
method
that allows
batteries to
charge in 10
minutes.Dendrites
puncture
battery parts
and short-
circuit the
cell. That
can lead to
a fire.
PHOTOGRAPH BY TONY LUONG January/February 2022 45