Thermo-mechano-electrochemical performance of the composition-graded electrode particles

Abstract

Higher capacity and longer life of the electrode is highly desired for the performance of lithium-ion batteries, which is subject to challenge of thermal and mechanical stability under working conditions. We proposed a thermo-mechano-electrochemical model for the diffusion-induced stresses of the electrodes with graded Young's modulus, partial molar volume, and thermal expansivity gained by modulating distribution of the compositions, i.e., concertation-grated substance. Modeling analysis revealed that lowering Young's modulus or raising thermal expansivity of the particle surface could protect the electrode from being cracked during lithiation or delithiation while reducing the partial molar volume could prevent fracture during lithiation. The ratio gain induced by graded Young's modulus is effective at any stress level. However, the value gains of graded partial molar volume and thermal expansivity enable the electrode to be prestressed.