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
[google_news title=”” keyword=”Lithium-ion batteries” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]
via Google News
The Latest on: Lithium-ion batteries
- DC fire officials urge precaution to prevent lithium-ion battery fireson February 23, 2024 at 7:26 pm
Fire officials are warning people to take precautions after yet another lithium-ion battery started a fire Thursday night in D.C. They’re in scooters, ...
- Aston Uni researchers pave the way for safer and greener lithium-ion batterieson February 23, 2024 at 10:14 am
Aston University researchers in Birmingham, England, are embarking on a groundbreaking exploration of gel electrolyte materials to enhance the safety and environmental sustainability of lithium-ion ...
- Florida House, Senate to vote on new safety rules for lithium-ion batterieson February 23, 2024 at 1:22 am
The state is hoping to cut down on dangerous fires sparked by exploding lithium-ion batteries that burn hotter and longer. The batteries are used in many electronic devices -- from cellphones to ...
- Homeowner blames charging cellphone for fire, urges caution with lithium-ion batterieson February 23, 2024 at 12:56 am
“I know my son plugged his cell phone in to charge right before he went to sleep,” Michelle Pilz, of Scandia, said about the morning their home was destroyed by a fire. “I believe it was the phone ...
- New safety rules for lithium-ion batteries headed for Florida House, Senate voteson February 22, 2024 at 7:06 pm
The Florida State Fire Marshal’s office will be able to create new rules for safely storing lithium-ion batteries under bills now headed for votes before the full Florida House and Senate.
- University Students in China Develop a Calcium Battery to Replace Lithium-Ion Batterieson February 21, 2024 at 7:28 pm
They draw oxygen from the air, eliminating the need for material storage within the battery itself, which has been a limiting factor ...
- San Francisco to set new rules for e-bikes, scooters powered by lithium-ion batterieson February 19, 2024 at 4:00 pm
The city's Board of Supervisors voted to create safety standards for some devices powered by lithium-ion batteries. Electric bikes and e-scooters continue to be part of San Francisco's attempt to ...
- Push for new product safety regulations on lithium-ion batteries as fire concerns growon February 16, 2024 at 6:55 pm
Lithium-ion batteries have exploded in popularity but also have been blamed for exploding and causing deadly house fires.
- Woodbury Fire Dept.: Lithium-ion batteries to blame for 5 house fires in past 4 monthson February 16, 2024 at 4:49 pm
Lithium-ion batteries are what's in your laptop, headphones, and most of the devices that need to be recharged. They have special cords for the wall and your device. If you use the wrong ones, that's ...
- Explained: Solid-state Batteries vs Lithium-ion Batterieson February 12, 2024 at 7:01 pm
The electrifying battle between solid-state batteries and lithium-ion batteries sparks innovation and potential breakthroughs in energy storage. Your browser does not ...
via Bing News