Skip to main content

Nano tubes may give the world better batteries

Scientists' method quenches lithium metal dendrites in batteries that charge faster, last longer

Date:
October 25, 2018
Source:
Rice University
Summary:
Scientists use thin films of multi walled carbon nano tubes to keep lithium metal from sprouting dendrites, tentacle-like growths that can cause batteries to fail. The strategy could be key to developing batteries that hold more energy and charge faster than current, ubiquitous lithium-ion batteries.
Rice University scientists are counting on films of carbon nano tubes to make high-powered, fast-charging lithium metal batteries a logical replacement for common lithium-ion batteries.
The Rice lab of chemist James Tour showed thin nano tube films effectively stop dendrites that grow naturally from unprotected lithium metal anodes in batteries. Over time, these tentacle-like dendrites can pierce the battery's electrolyte core and reach the cathode, causing the battery to fail.
That problem has both dampened the use of lithium metal in commercial applications and encouraged researchers worldwide to solve it.
Lithium metal charges much faster and holds about 10 times more energy by volume than the lithium-ion electrodes found in just about every electronic device, including cellphones and electric cars.
"One of the ways to slow dendrites in lithium-ion batteries is to limit how fast they charge," Tour said. "People don't like that. They want to be able to charge their batteries quickly."The Rice team's answer, detailed in Advanced Materials, is simple, inexpensive and highly effective at stopping dendrite growth, Tour said.
"What we've done turns out to be really easy," he said. "You just coat a lithium metal foil with a multi walled carbon nano tube film. The lithium dopes the nano tube film, which turns from black to red, and the film in turn diffuses the lithium ions."
"Physical contact with lithium metal reduces the nano tube film, but balances it by adding lithium ions," said Rice postdoctoral researcher Rodrigo Salvatierra, co-lead author of the paper with graduate student Gladys López-Silva. "The ions distribute themselves throughout the nano tube film."
When the battery is in use, the film discharges stored ions and the underlying lithium anode refills it, maintaining the film's ability to stop dendrite growth.
The tangled-nano tube film effectively quenched dendrites over 580 charge/discharge cycles of a test battery with a sulfurised-carbon cathode the lab developed in previous experiments. The researchers reported the full lithium metal cells retained 99.8 percent of their coulombic efficiency, the measure of how well electrons move within an electrochemical system.
Story Source:
Materials provided by Rice University. Original written by Mike Williams. Note: Content may be edited for style and length.

Comments

Post a Comment

Popular posts from this blog

Major surgery associated with small, long term decline in brain functioning

Major surgery is associated with a small long-term decline in cognitive functioning -- equivalent, on average, to less than five months of natural brain ageing, finds a study in  The BMJ  today. But the odds of substantial cognitive decline also increase after surgery -- approximately doubling -- although the likelihood of this is much lower than after admission to hospital for a medical condition, the findings show. Cognitive decline is the gradual loss of brain functioning that occurs with ageing. It often starts decades before the conventional definition of old age and accelerates with ageing and the presence of an increasing number of underlying health conditions. Certain health issues, such as stroke, can lead to a large "step change" in cognitive decline, and there have been concerns that surgery might also do this, with some patients refusing beneficial surgical procedures as a result, say the researchers. Few previous studies have looked at the potential im...
Post a Comment
Read more

Dark matter may be older than the Big Bang

Dark matter, which researchers believe make up about 80% of the universe's mass, is one of the most elusive mysteries in modern physics. What exactly it is and how it came to be is a mystery, but a new Johns Hopkins University study now suggests that dark matter may have existed before the Big Bang. The study, published August 7 in  Physical Review Letters , presents a new idea of how dark matter was born and how to identify it with astronomical observations. "The study revealed a new connection between particle physics and astronomy. If dark matter consists of new particles that were born before the Big Bang, they affect the way galaxies are distributed in the sky in a unique way. This connection may be used to reveal their identity and make conclusions about the times before the Big Bang too," says Tommi Tenkanen, a postdoctoral fellow in Physics and Astronomy at the Johns Hopkins University and the study's author. While not much is known about its origins,...
Post a Comment
Read more

Scientists challenge notion of binary sexuality with naming of new plant species

A collaborative team of scientists from the US and Australia has named a new plant species from the remote Outback. Bucknell University biology postdoctoral fellow Angela McDonnell and professor Chris Martine led the description of the plant that had confounded field biologists for decades because of the unusual fluidity of its flower form. The discovery, published in the open access journal  PhytoKeys , offers a powerful example of the diversity of sexual forms found among plants. The new species of bush tomato discovered in remote Australia provides a compelling example of the fact that sexuality among Earth's living creatures is far more diverse -- and interesting -- than many people likely realize. Bucknell University postdoctoral fellow Angela McDonnell and biology professor Chris Martine led the study following an expedition last year to relocate populations of the new plant, which were first noted by Australian botanists during the 1970s. Herbarium specimens from th...
Post a Comment
Read more