Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Low-cost battery from waste graphite

11.10.2017

Lithium ion batteries are flammable and the price of the raw material is rising. Are there alternatives? Yes: Empa and ETH Zürich researchers have discovered promising approaches as to how we might produce batteries out waste graphite and scrap metal.

Kostiantyn Kravchyk works in the group of Maksym Kovalenko. This research group is based at both ETH Zurich and in Empa’s Laboratory for Thin Films and Photovoltaics. The two researchers’ ambitious goal at the Empa branch is to make a battery out of the most common elements in the Earth’s crust – such as magnesium or aluminum.


Kish graphite is a waste product from steel production. It could be used to make a cheap rechargeable battery out of abundant materials.

Empa / ETH Zürich

These metals offer a high degree of safety, even if the anode is made of pure metal. This also offers the opportunity to assemble the batteries in a very simple and inexpensive way and to rapidly upscale the production.

In order to make such batteries run, the liquid electrolyte needs to consist of special ions that do not crystallize at room temperature – i.e. form a kind of melt. The metal ions move back and forth between the cathode and the anode in this “cold melt”, encased in a thick mantle of chloride ions. Alternatively, large but lightweight organic anions, which are metal-free, could be used.

This does come with a problem, though: where are these “thick” ions supposed to go when the battery is charged? What could be a suited cathode material? By way of comparison: in lithium ion batteries, the cathode is made of a metal oxide, which can easily absorb the small lithium cations during charging. This does not work for such large ions, however. In addition, these large anions have an opposite charge to the lithium cations.

Battery turned “upside down”

To solve the problem, Kovalenko’s team had a trick up their sleeves: the researchers turned the principle of the lithium ion battery upside down. In conventional Li-ion batteries, the anode (the negative pole) is made of graphite, the layers of which (in a charged state) contain the lithium ions.

In Kovalenko’s battery, on contrary, the graphite is used as a cathode (the positive pole). The thick anions are deposited in-between the graphene layers. In Kovalenko’s battery, the anode is made of metal.

Kravchyk made a remarkable discovery while searching for the “right” graphite: he found that waste graphite produced in steel pro-duction, referred to as ”kish graphite”, makes for a great cathode material. Natural graphite also works equally well – if it is supplied in coarse flakes and not ground too finely or into folded, non-flake shapes.

The reason: the graphite layers are open at the flakes’ edges and the thick anions are thus able to slip into the structure more easily. The fine-ground graphite normally used in lithium ion batteries, however, is ill-suited for Kovalenko’s battery: by grinding the graphite particles, the layers become creased like crumpled-up paper. Only small lithium ions are able to penetrate this crumpled graphite, not the new battery’s thick anions.

The graphite cathode battery constructed from steel production “kish graphite” or raw, natural graphite flakes has the potential to become highly cost-effective. And if the first experiments are anything to go by, it is also long-lasting. For several months, a lab system survived thousands of charging and discharging cycles.

“The aluminum chloride – graphite cathode battery could last decades in everyday household use,” explains Kravchyk and adds “similar demonstrations, but further increased battery voltages, without compromising capacities, and of even lighter elements are on the way and will offer further increase in energy densities from current 60 Wh kg-1 to above 150 Wh kg-1”

Weitere Informationen:

https://www.empa.ch/web/s604/waste-graphite-batteries

Rainer Klose | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

More articles from Power and Electrical Engineering:

nachricht How electric heating could save CO2 emissions
17.12.2018 | Technische Universität München

nachricht Data use draining your battery? Tiny device to speed up memory while also saving power
14.12.2018 | Purdue University

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Data storage using individual molecules

Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.

Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Pressure tuned magnetism paves the way for novel electronic devices

18.12.2018 | Materials Sciences

New type of low-energy nanolaser that shines in all directions

18.12.2018 | Physics and Astronomy

NASA research reveals Saturn is losing its rings at 'worst-case-scenario' rate

18.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>