Modeling of diffusion-induced stresses of spherical composition-gradient electrodes in lithium-ion batteries

School of Aerospace Engineering and Applied Mechanics, Tongji University, No. 1239 Siping road, Shanghai 200092, P.R. China

^a e-mail: blzheng@tongji.edu.cn

Received: 21 October 2014
Revised: 3 January 2015
Accepted: 13 March 2015
Published online: 24 April 2015

Abstract

The novel spherical composition-gradient electrode materials have been proved to exhibit an excellent capacity, cyclability and thermal stability. To investigate the mechanism of excellent electrochemical performances of such materials, a model for spherical electrodes with gradient material properties is developed and diffusion-induced stresses (DISs) of the electrodes are studied. The results show that the distributions of diffusion-induced stresses in spherical composition-gradient electrodes are found to be continuous and smooth, which can decrease the mechanical degradation, resulting in an increase in electrochemical performance of lithium-ion batteries (LIBs). The suggestion for the criterion for the selection of the core and shell materials has been made that the electrode should be design to be softer at surface and harder at center.