New lithium-ion battery could power electric vehicles

Posted by Chris Nova

Car companies are rapidly developing electric and hybrid electric vehicles. One of the challenges they deal with is discovering a proper energy storage system. They may now have a solution to that problem.

Lithium-ion batteries, which are currently the power source for a lot of small consumer electronics devices, could solve this problem. At the moment they need more improvements in terms of energy density and power density to be used efficiently in electric powered vehicles.

According to PhysOrg.com, in a new study researchers have developed a type of lithium –ion battery with an anode and cathode that involve new battery chemistries, which improves the battery’s performance and possibly making it acceptable for electric vehicles.
    
The scientists, Jusef Hassoun, Ki-Soo Lee, Yang-Kook Sun, and Bruno Scrosati, from the University of Rome Sapienza in Rome, Italy, and Hanyang University in Seoul, South Korea, have had their study on the advanced lithium-ion battery published in a recent issue of the Journal of the American Chemical Society.
    
Their research expands on the team’s prior research into the development of advanced lithium-ion battery chemistries. The secret to the high performance is in the battery’s electrode components. For this, the scientists use a tin-carbon anode and a cathode made of lithium manganese oxide doped with nickel and cobalt. A lithium-ion battery with this unique electrode combination has never been reported.
    
“The battery is based on a new combination between a high-voltage cathode and a nanostructured anode material,” Scrosati told PhysOrg.com. “The battery operates with a very stable capacity at high discharge rates with no significant capacity losses throughout the entire cycling test.”
    
The new configuration of electrode materials yields certain advantages for the overall battery. As the researchers previously been able to demonstrate, the tin-carbon anode has a high cycling life of hundreds of cycles without a loss in capacity, as well as discharge-charge efficiency nearly reaching 100%. By using a surface treatment on the anode, the researchers could improve the capacity even more.

The new manganese-based cathode materials are more abundant, less costly, more environmentally sound, and have a higher stability at low temperatures compared to the lithium cobalt oxide cathode used in traditional lithium-ion batteries. Also, in the design of the new cathode, the researchers carefully manipulated the composition, particle size, shape, morphology, and tap density.

“The battery has: 1) a high volumetric and gravimetric energy density; 2) a high rate capability due to the nano-structured characteristics of the electrode materials; 3) an excellent cycle life; and 4) low cost, due to the use of electrode materials based on abundant elements,” Scrosati said.

The cathode’s high voltage and high capacity gives the new battery a higher energy density (170 Wh/kg at average discharge voltage of 4.2 volts) than the regular lithium-ion batteries consumers are used to.

“The conventional lithium-ion batteries have an energy density of about 120-150 Wh/kg, depending on the used cathode material,” Scrosati said. “Generally, commercial lithium battery cells using layer structure cathode materials, for instance, NCA and NMC, deliver from 100 to 150 Wh/kg.”

Basically, the high energy density, stable cycle life, and high rate capabilities show that the battery looks very promising for powering electric vehicles.

“In summary, with respect to those using conventional lithium-ion batteries, electric vehicles using our battery may assure: 1) a longer driving range (210 km/charge vs. 150 km/charge due to the higher energy density; 2) a higher top speed; 3) a lower cost; and 4) better overall performance especially at low temperatures,” Scrosati said.