How to boost lithium battery performance – just add crushed silicon
Rice University researchers Madhuri Thakur, left, and Sibani Lisa Biswal with their crushed silicon anode material (Photo: Jeff Fitlow)
Researchers at Rice University and Lockheed Martin may have developed a low-cost method of creating longer-lasting, high-capacity lithium-ion batteries. Currently graphite is used as the anode in commercial li-ion products, despite the fact that a silicon anode could potentially store ten times more lithium ions. The team says it has solved one of the problems associated with silicon, which nearly triples the energy density of current li-ion designs.
Engineer Sibani Lisa Biswal and research scientist Madhuri Thakur had been working on a porous silicon film with sponge-like properties, but wanted to create something more applicable to the current battery manufacturing process.
They discovered that by crushing the film, the resulting powder had a surface area 50 times that of regular crushed silicon. The result is an anode material that can hold a charge of 1,000 milliamp hours per gram compared to graphite anodes, which store 350 mAh/g – and that's only a third of its theoretical capacity.
Both vials contain the same amount of crushed silicon, but the vial on the right contains the treated powder with 50 times more surface area (Photo: Jeff Fitlow)
“We’re truly excited about this breakthrough and are looking forward to transitioning this technology to the commercial marketplace,” said Lockheed Martin researcher Mark Isaacson, despite questions of cost and scale that need to be addressed.
The team is working on a completed battery that will test their design, and part of that will be finding the best silicon-friendly cathode material. That said, if all goes well this could be the long overdue breakthrough in battery technology that electric vehicles and mobile electronic device manufacturers have been waiting for.
Source: Rice University
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Jason is a freelance writer based in central Canada with a background in computer graphics. He has written about hundreds of humanoid robots on his website Plastic Pals and is an avid gamer with an unsightly collection of retro consoles, cartridges, and controllers.
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Silicon has always shown great energy density, The problem with silicon has been longevity. So this announcement really only has value for EVs if it can retain those energy density for 1000 cycles. Otherwise it would make a great primary battery (for toys and flashlights) but not really be useful for EVs.
"They discovered that by crushing the film, the resulting powder had a surface area 50 times that of regular crushed silicon"
I'm not generally suspicious, nor do I wear an alfoil hat, but how is such an obvious process improvement just coming to light?
As already been stated, Silicon has a high theoretical energy density and is a candidate as a electrode-active material for LiB, but is it stable over a high number of charge and discharges cycles?
Fretting Freddy the Ferret pressing the Fret
Hi Nairda, The surface area of the film is porous where as the the crushed silicon is non-porous. The process is obvious, but it come into light in 2010, when the the crushed mesoporous silicon is used for bio medical application and lift-off porous film in battery application in 2012.
Thank you for the reply.
Does the process used to create porous Silica let you regulate the density of the end result, i.e. -size of air bubbles in the structure?
Same question for the crushing process and size of resultant grains. Was the aim to create a grain size of a specific size, or just even distribution between 2 and 50 nm ?
I'm just curious if your initial testing was just a bold proof of concept to validate the benefit of crushed silica in over graphite, or if the process was optimised?
Have you considered porous crushed graphite? :)
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