Figure shows to design always conducting Si-CNT nanostructure, the weak Si/CNT interface contributes to cracks in Si in Si-CNT core shell structure during lithiation (as seen in the computed stress field model and by situ-TEM). ACS Nano7, 2717 (2013)
Developing batteries with extended lifetimes will significantly enhance the performance and reduce cost of future of electric vehicles, since such batteries will not have to be oversized and over-engineered, as is now the case. Currently, all life models depend on parameter fitting to data that often requires months to years of battery testing to obtain.
In order to computationally screen and design future battery materials for improved durability, we need to be able to predict failure starting from materials’ properties and structures without using non-physical fitting parameters. We have used DFT to predict elastic and fracture properties of electrode materials and their interfaces integrated into meso-structures to predict the lithiation-induced stress and failure of composite electrodes. Many of our predictions have been confirmed by in-situ experiments.
Currently, we are integrating structural evolution and chemical degradations into a battery predictive life model. We are using these methods to develop high capacity and long-lasting nano-structured electrodes.
- “A beaded-string silicon anode”, C.F. Sun, K. Karki, Z. Jia, H. Liao, Y. Zhang, T. Li, Y. Qi, J. Cummings, G. Y.H. Wang, ACS Nano 7, 2717 (2013)
- “Li segregation induces structure and strength changes at the amorphous Si/Cu interface”, M.E. Stournara, X. Xiao, Y. Qi, P. Johari, P. Lu, B.W. Sheldon, H. Gao, V.B. Shenoy, Nano Letters 13, 4759 (2013)
- “In-situ observation of strains during lithiation of a graphite electrode”, Y. Qi and S.J. Harris, J. Electrochemical Society 157, A741, (2010)
Kwang Jin Kim, Dr. Sung Yup Kim