Doping Lithium-ion Batteries to Make Them Safer

Could help enable safer, more powerful next-generation batteries

2 min read
Doping Lithium-ion Batteries to Make Them Safer
Illustration: W. Li/Nature Communications

Fires resulting from the catastrophic failure of lithium-ion batteries could be prevented with chemical additives, say researchers at Stanford University.

When lithium-ion batteries overheat, they can burn through internal pockets, burst into flames, and even explode. One reason such damage can occur is the formation of dendrites—finger-like deposits of lithium that can grow long enough to pierce the barrier between a lithium-ion battery's halves and cause it to short out.

Dendrites form when a battery electrode degrades and metal ions deposit onto the electrode's surface. Previously, scientists at Stanford developed a lithium-ion battery that can detect when dendrites start to puncture the barrier between its halves and warn that it needs to be replaced.

In their latest work, detailed in the 17 June online edition of the journal Nature Communications, the Stanford researchers used chemicals designed to prevent dendrite formation. These get added to the battery's electrolyte, the fluid in which electrons flow between the battery's electrodes.

One of the additives, lithium nitrate, has been researched for a long time as a way to boost battery performance. The other, lithium polysulfide, has been considered a nuisance; it forms when a sulfur electrode degrades and can wreck lithium metal electrodes. But together, these additives can synergistically react with lithium metal to form a stable coating that protects the electrode from further degradation.

In experiments with coin cell batteries similar to the ones that power calculators and watches, the additives prevented dendrite formation, with harmless pancake-like deposits forming instead. Such batteries could operate at 99 percent efficiency after more than 300 charge-discharge cycles, compared with less than 92 percent efficiency after 180 cycles for batteries doped with only lithium nitrate.

This approach could help remove a major barrier to developing lithium-sulfur and lithium-air batteries, which can store up to 10 times more energy per unit mass than batteries now used in consumer electronics and electric cars, but have a tendency to form dendrites. It may also work for batteries made with metals such as magnesium, calcium, or aluminum, which also could store much more energy than today's batteries.

The Conversation (0)

Deep Learning Could Bring the Concert Experience Home

The century-old quest for truly realistic sound production is finally paying off

12 min read
Image containing multiple aspects such as instruments and left and right open hands.
Stuart Bradford

Now that recorded sound has become ubiquitous, we hardly think about it. From our smartphones, smart speakers, TVs, radios, disc players, and car sound systems, it’s an enduring and enjoyable presence in our lives. In 2017, a survey by the polling firm Nielsen suggested that some 90 percent of the U.S. population listens to music regularly and that, on average, they do so 32 hours per week.

Behind this free-flowing pleasure are enormous industries applying technology to the long-standing goal of reproducing sound with the greatest possible realism. From Edison’s phonograph and the horn speakers of the 1880s, successive generations of engineers in pursuit of this ideal invented and exploited countless technologies: triode vacuum tubes, dynamic loudspeakers, magnetic phonograph cartridges, solid-state amplifier circuits in scores of different topologies, electrostatic speakers, optical discs, stereo, and surround sound. And over the past five decades, digital technologies, like audio compression and streaming, have transformed the music industry.

Keep Reading ↓Show less