Kejie Zhao's blog

The inaugural Future Faculty Symposium (FFS) will be part of the 60th Society of Engineering Science Annual Conference (SES 2023) at the University of Minnesota in October, please see attached flyer. The goal is to provide a venue for senior PhDs/Postdocs to showcase their reserach and facilitate recruiting dynamics.

Kejie Zhao, School of Mechanical Engineering, Purdue University

Dear Colleagues,

Now receiving new submissions for the special issue on mechanics in energy materials.

A variety of questions remain open in the new form of nanotwins in Ni, welcome any comments! 

Dear Colleagues:

please consider to attend the symposium titled" Mechanics in Energy Storage and Conversion" as part of the society of engineering science 52nd annual technical meeting to be held at Texas A&M, Oct 26-28, 2015.

Dear Colleagues,

Please consider to attend the symposium entitled  "Mechanics of Materials in Energy Technologies"  at the occasion of ASME 2015 Applied Mechanics and Materials Conference, 6.29-7.1, 2015, in Seattle.The conference occurs every four years and covers all aspects of mechanics and materials: theoretical, experimental, and computational.

The description of the symposium is below.

http://pubs.acs.org/doi/abs/10.1021/nl503776u

Dear Colleagues,

Please consider to attend the symposium entitled  "Lithium ion batteries - when chemistry meets mechanics"  at the occasion of the Joint Society of Engineering Science (SES) 50th Annual Technical Meeting and ASME-AMD Annual Summer Meeting, July 28-31, 2013, at Brown University.

The description of the symposium is attached below.

The following speakers will contribute invited talks in the symposium: Yi Cui, William D. Nix, Martin Bazant, Brian Sheldon, Gleb Yushin, Scott Mao, Reiner Moenig, and Yue Qi

http://pubs.acs.org/doi/abs/10.1021/jp307221q 

http://pubs.acs.org/doi/abs/10.1021/nl302261w 

In a novel design of lithium-ion batteries, hollow electrode particles coated with stiff shells are used to mitigate mechanical and chemical degradation.  In particular, silicon anodes of such core-shell nanostructures have been cycled thousands of times with little capacity fading.  To reduce weight and to facilitate lithium diffusion, the shell should be thin.  However, to avert fracture and debonding from the core, the shell must be sufficiently thick.

Silicon can host a large amount of lithium, making it a promising electrode for high-capacity lithium-ion batteries.  Recent experiments indicate that silicon experiences large plastic deformation upon Li absorption, which can significantly decrease the stresses induced by lithiation and thus mitigate fracture failure of electrodes. These issues become especially relevant in nanostructured electrodes with confined geometries.

Silicon can host a large amount of lithium, making it a promising electrode for high-capacity lithium-ion batteries.  Upon absorbing lithium, silicon swells several times its volume; the deformation often induces large stresses and pulverizes silicon.

During charging or discharging of a lithium-ion battery, lithium is extracted from one electrode and inserted into the other.  This extraction-insertion reaction causes the electrodes to deform.  An electrode is often composed of small active particles in a matrix.  If the battery is charged at a rate faster than lithium can homogenize in an active particle by diffusion, the inhomogeneous distribution of lithium results in stresses that may cause the particle to fracture.  The distributions of lithium and stress in a LiCoO2 particle

The stress-strain behavior and incipient yield surface of nanoporous single crystal copper are studied by the molecular dynamics (MD) method. The problem is modeled by a periodic unit cell subject to multi-axial loading. The loading induced defect evolution is explored. The incipient yield surfaces are found to be tension-compression asymmetric. For given void volume fraction, apparent size effects in the yield surface are predicted: the smaller behaves stronger.