Lithium-ion batteries

Batteries for Flying Cars

  • By Jenny Stein
  • 8 May 2020

Venkat Viswanathan, Associate Professor of Mechanical Engineering at CMU, describes their latest paper in Nature Materials and the 5-year effort to understand electrodeposition instabilities at solid-solid interfaces, leading to high-performing lithium metal based batteries:

In the fall of 2015, we began exploring the role of mechanical properties in stabilizing lithium electrodeposition at solid-solid interfaces in solid state batteries. Previous results from an elegant linear stability analysis performed by Monroe and Newman suggested that solids with sufficiently large moduli could block dendrite growth due to the stabilizing role of the hydrostatic part of the stress.

Venkat Viswanathan Quoted About Lithium-Air Batteries in Chemistry World

  • By Burcu Ozden
  • 17 April 2018

Chemistry World quoted Venkat Viswanathan on the cycle life of lithium-air batteries. These batteries hold a charge greater by a factor of nine compared to lithium-ion. In interpreting the batteries’ cycle life, Viswanathan expresses a distanced view. A traditional lithium-ion battery’s life is measured by its electrical discharge. In a lithium-air battery, discharge from the reaction of lithium and oxygen determines cycle life. But because air comprises more elements than just oxygen, Viswanathan wonders how many side reactions in the electricity delivery artificially boost the cycle life. Mitigating these side reactions should pave the way to developing long-lasting lithium-air batteries.

In Pursuit of an Immortal Cathode: Electrical Energy Storage using MnO2 Nanowires that Never Die

Reginald Penner
Friday, March 16, 2018 - 9:30am to 10:30am

Rechargeable lithium ion (Li+) batteries lose their ability to store charge over time.  Whether they power your phone, your laptop, or your automobile, after 500-1000 recharge cycles they lose 20-40% of their capacity and must be replaced. Sony introduced the first commercial  Li+ battery in 1990, but 27 years later our understanding of WHY they fail is still in its infancy.  Li+ batteries have four parts:  An anode (usually graphite), a cathode (usually a metal oxide), a separator membrane that is located between them, and a salt solution containing Li+.  In our research, we have focused attention on one cathode material called ∂-MnO2.   Our goals have been to increase the amount of energy we can store, to increase the rate at which we can deliver this energy, and to extend the lifetime of the cathode.  Now, you might think that the worst way to make a battery cathode last longer would be to make it smaller!  But we have discovered a process for preparing ∂-MnOnanowires  - just 60 – 600 nm in diameter and up to a centimeter in length – that never fail, and rarely lose any energy storage capacity, across 100,000 charge/recharge cycles.   In this talk, I’ll discuss these unusual nanomaterials and what they may mean for the future of electrical energy storage.

Storage at the Threshold: Li-ion Batteries and Beyond

George Crabtree
Friday, October 14, 2016 - 1:00pm to 2:00pm

The high energy density and low cost of lithium-ion batteries have created a revolution in personal electronics through laptops, tablets, smart phones and wearables, permanently changing the way we interact with people and information. We are at the threshold of similar transformations in transportation to electric cars and in the electricity grid to renewable generation, smart grids and distributed energy resources. Many aspects of these transformations require new levels of energy storage performance and cost that are beyond the reach of Li-ion batteries....

Venkat Viswanathan Awarded Funding to Stop Dendrite Formation in Li-ion Batteries

  • By Aude Marjolin
  • 19 September 2016

Energy expert Venkat Viswanathan have received funding from the U.S. Department of Energy’s Advanced Research Projects Agency – Energy (ARPA-E) to study the use of dendrite-blocking polymers in lithium-ion batteries. 

When charged repeatedly, lithium-ion batteries run the risk of overheating, and even catching fire. This is due to the formation of dendrites, or microscopic fibers of lithium that can form during the charging cycle. Over time, these dendrites can grow long enough that they connect the battery’s electrodes to one another, causing the battery to short-circuit and become a potential hazard. In order to fully implement future lithium-ion battery technologies, which could greatly increase the battery power of our smartphones, electric vehicles, and more, engineers need to find a way to stop these dendrites from forming.