The capacity of lithium-ion batteries might be increased by six times by using anodes made of silicon instead of graphite. A team from the Helmholtz-Zentrum Berlin (HZB) Institute of Soft Matter and Functional Materials has observed for the first time in detail how lithium ions migrate into thin films of silicon. It was shown that extremely thin layers of silicon would be sufficient to achieve the maximal load of lithium.
The team was able to show through neutron measurements made at the Institut Laue-Langevin in Grenoble, France, that lithium ions do not penetrate deeply into the silicon. During the charge cycle, a 20-nm anode layer develops containing an extremely high proportion of lithium. This means extremely thin layers of silicon would be sufficient to achieve the maximal load of lithium.
Lithium-ion batteries provide laptops, smart phones, and tablet computers with reliable energy. However, electric vehicles have not gotten as far along with conventional lithium-ion batteries. This is due to currently utilised electrode materials such as graphite only being able to stably adsorb a limited number of lithium ions, restricting the capacity of these batteries. Semiconductor materials like silicon are therefore receiving attention as alternative electrodes for lithium batteries. Bulk silicon is able to absorb enormous quantities of lithium. However, the migration of the lithium ions destroys the crystal structure of silicon. This can swell the volume by a factor of three, which leads to major mechanical stresses.
Observation during charging cycle
Now a team from the HZB Institute for Soft Matter and Functional Materials headed by Prof. Matthias Ballauff has directly observed for the first time a lithium-silicon half-cell during its charging and discharge cycles. “We were able to precisely track where the lithium ions adsorb in the silicon electrode using neutron reflectometry methods, and also how fast they were moving”, comments Dr. Beatrix-Kamelia Seidlhofer, who carried out the experiments using the neutron source located at the Institute Laue-Langevin.
Lithium-rich layer of only 20 nanometer
She discovered two different zones during her investigations. Near the boundary to the electrolytes, a roughly 20-nm layer formed having extremely high lithium content: 25 lithium atoms were lodged among 10 silicon atoms. A second adjacent layer contained only one lithium atom for ten silicon atoms. Both layers together are less than 100 nm thick after the second charging cycle.
Theoretical maximum capacity
After discharge, about one lithium ion per silicon node in the electrode remained in the silicon boundary layer exposed to the electrolytes. Seidlhofer calculates from this that the theoretical maximum capacity of these types of silicon-lithium batteries lies at about 2300 mAh/g. This is more than six times the theoretical maximum attainable capacity for a lithium-ion battery constructed with graphite (372 mAh/g).
Less is more
These are substantial findings that could improve the design of silicon electrodes: very thin silicon films should be sufficient for adsorbing the maximum possible amount of lithium, which in turn would save on material and especially on energy consumed during manufacture – less is more!
The Latest on: Lithium-ion batteries
via Google News
The Latest on: Lithium-ion batteries
- Finding the cause of capacity loss in a metal-oxide battery material on May 24, 2019 at 10:00 am
Because of their high energy-storage density, materials such as metal oxides, sulfides, and fluorides are promising electrode materials for lithium-ion batteries in electric vehicles and other ... […]
- How to Tell if Your Nikon Battery is Fake on May 24, 2019 at 9:51 am
“It has come to our attention that we unfortunately received a subpar batch of Nikon EN-EL15b rechargeable lithium-ion batteries,” B&H wrote in an email to affected customers. “Since it is ... […]
- Inventor of the lithium-ion battery, Professor John Goodenough, awarded Royal Society’s prestigious Copley Medal on May 24, 2019 at 6:48 am
Professor John Goodenough from the Cockrell School of Engineering at The University of Texas at Austin has been awarded the Royal Society’s Copley Medal, the world’s oldest scientific prize. Already a ... […]
- Baking a "Jellyroll": How Batteries Get Made on May 24, 2019 at 3:34 am
Every day around the globe, millions of run-of-the-mill lithium-ion batteries are cranked out. Typically these workhorses of the electronic economy are produced in cavernous, highly automated ... […]
- Adding Giant Batteries To This Hydro Project Creates A 'Virtual Dam' With Less Environmental Impact on May 23, 2019 at 1:59 pm
Grid-scale batteries on the other hand use rechargeable lithium-ion technology similar to that found in smartphones and electric cars, aggregated at scale to deliver the same electricity storage ... […]
- B&H is Replacing a ‘Subpar’ (i.e. Fake) Batch of Nikon Batteries on May 22, 2019 at 11:58 am
“It has come to our attention that we unfortunately received a subpar batch of Nikon EN-EL15b rechargeable lithium-ion batteries,” B&H writes. “Since it is impossible for us to ascertain ... […]
- Lithium Ion Battery Market Demand Continue to Grow at CAGR of 18% During the Forecast Period of 2019 to 2025: IndustryARC on May 22, 2019 at 4:30 am
Apart from electric mobility, Li-ion batteries are also a key energy storage medium for large scale application such as the Energy Storage Systems (ESS), which are being widely used in Distributed ... […]
- Phase evolution of conversion-type electrode for lithium ion batteries on May 20, 2019 at 1:53 pm
Batteries with conversion-type electrodes exhibit higher energy storage density but suffer much severer capacity fading than those with the intercalation-type electrodes. The capacity fading has been ... […]
- Graphite lithium-ion batteries get a boost from halogen intercalation on May 16, 2019 at 7:52 am
Graphite battery boost. Helper halides bring unprecedented capacity and excellent cyclability. Credit: iStock alxpin Lithium ion batteries are a useful and powerful energy storage option. Commonly ... […]
- Lithium Ion Battery Market Market By Industry Growth, Trend and Forecast 2024 on May 15, 2019 at 12:22 am
May 15, 2019 (Heraldkeeper via COMTEX) -- Latest Report on Lithium Ion Battery Market 2019: New Study Presents a Qualitative & Quantitative Analysis with Top Key Players Like Tesla, Panasonic, Samsung ... […]
via Bing News