Electronics

Silk-derived material could boost battery performance

Silk-derived material could bo...
Natural silk can be processed into a material suitable for use as a lithium-ion battery anode, with impressive results (Photo: Shutterstock)
Natural silk can be processed into a material suitable for use as a lithium-ion battery anode, with impressive results (Photo: Shutterstock)
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Natural silk can be processed into a material suitable for use as a lithium-ion battery anode, with impressive results (Photo: Shutterstock)
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Natural silk can be processed into a material suitable for use as a lithium-ion battery anode, with impressive results (Photo: Shutterstock)

Next-generation lithium-ion batteries may hold more charge for a greater number of cycles thanks to a new material derived from natural silk. Scientists at the Beijing Institute of Technology found that not only does their regenerated silk fibroin material work for over 10,000 cycles but it also stores five times more lithium than graphite, which is the most common choice for the anode (negative electrode) in lithium-ion batteries.

Scientists and battery manufacturers have tried all sorts of possible graphite replacements to boost performance, including high-quartz sand, which tripled performance in coin-sized batteries. But nothing has yet made it to widespread use.

The Beijing-based researchers challenged themselves to find a sustainable biorenewable source that would outperform graphite. They found that natural silk could be processed to create carbon-based nanosheets, which they then incorporated in prototype batteries and supercapacitors.

The resulting batteries had a capacity of 1,865 mAh/g – five times greater than the theoretical capacity of graphite (372 mAh/g) – at a current density of 0.1 A/g and they retained a high cycle stability of around 92 percent after 10,000 cycles. In other words, they take a much longer time to run out and they can be charged and discharged many times more than conventional lithium-ion batteries and the performance boost is comparable across a large range of current densities.

The researchers believe that their method could easily be scaled up for commercial use, and they note that their material could also find use in sodium-ion batteries, hydrogen storage, and other hybrid energy storage devices.

A paper describing the research was published in the journal ACS Nano.

Source: American Chemical Society

4 comments
Don Duncan
The race to build a better battery is white hot. I have waited 30 years for a practical EV so I watch/read about the results hoping to see a break thru go into production. At 72 I can't wait much longer. I have decided to buy the new affordable Tesla in 2017.
Anne Ominous
We've seen an AWFUL LOT of these stories about improved electrodes for lithium batteries. But not even one of them has yet made it to market. I'll believe it when I see it.
Not that I don't believe the technology is there. I do. But in a way it has been like photovoltaics: if half the claimed "improvements" ever made it into production, they'd be 400% efficient and cost 0.1¢ per kW to install.
pmshah
Nothing is likely to happen until and unless some US corporation can patent the process / product.
StWils
Anne is correct again but PmShah is off a bit. Corporations will hesitate unless they can screw everyone else on profit first, especially the inventors. A few years ago an American researcher used feathers to create a carbon fibre/graphite substrate with a gigantic surface area. That is what is has occurred here with silk. Surface area is what governs the speed and mobility of lithium ions. I would like to know how silk compares to feathers. Certainly feathers would be cheap since the billion pounds plus produced in just the U.S. are a nuisance waste product of poultry production. Also there may be similar advantages possible from other natural derived materials.