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Carbon nanotubes the answer to making efficient batteries: Study

Nanotube films effectively stops dendrites that grow from unprotected lithium metal anodes in batteries

Turns out, the secret to making better batteries lies in using carbon nanotubes.

A research led by Rice University scientists, that was published in Advanced Materials journal, confirmed the benefits of using carbon nanotubes.

They found out that films of carbon nanotubes make high-powered, fast-charging lithium metal batteries, which is a worthy replacement for the commonly used lithium-ion batteries.

Lead researcher James Tour said that nanotube films effectively stops dendrites that grow from unprotected lithium metal anodes in batteries, and over time, can pierce the battery's electrolyte core and reach the cathode, eventually resulting in a battery failure.

The good thing about Lithium metal is that it charges much faster and holds 10 times more energy by volume than the lithium-ion electrodes.

"One of the ways to slow dendrites in lithium-ion batteries is to limit how fast they charge," Tour said.

He further mentioned that a coat of lithium metal foiled with a multiwalled carbon nanotube film does the job.

"The lithium dopes the nanotube film, which turns from black to red, and the film, in turn, diffuses the lithium ions," he added.

According to another lead researcher, Rodrigo Salvatierra, physical contact with lithium metal reduces the nanotube film and goes on to balances it by adding lithium ions.

"The ions distribute themselves throughout the nanotube film," Salvatierra added.

When the battery is in use, the film discharges stored ions and the underlying lithium anode refills it which helps in maintaining the film's ability to stop dendrite growth altogether.

The test revealed that the tangled-nanotube film effectively destroyed dendrites over 580 charge/discharge cycles of a test battery when used with a sulfurised-carbon cathode.

The researchers even reported that the full lithium metal cells retained 99.8 per cent of their efficiency.

(Source)

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