Progressive Damage Analysis for Spherical Electrode Particles with Different Protective Structures for a Lithium-Ion Battery.

Abstract

Charge-discharge in a lithium-ion battery may produce electrochemical adverse reactions in electrodes as well as electrolytes and induce local inhomogeneous deformation and even mechanical fracture. An electrode may be a solid core-shell structure, hollow core-shell structure, or multilayer structure and should maintain good performance in lithium-ion transport and structural stability in charge-discharge cycles. However, the balance between lithium-ion transport and fracture prevention in charge-discharge cycles is still an open issue. This study proposes a novel binding protective structure for lithium-ion battery and compares its performance during charge-discharge cycles with unprotective structure, core-shell structure and hollow structure. First, both solid and hollow core-shell structures are reviewed, and their analytical solutions of radial and hoop stresses are derived. Then, a novel binding protective structure is proposed to well-balance lithium-ionic permeability and structural stability. Third, the pros and cons of the performance at the outer structure are investigated. Both analytical and numerical results show that the binding protective structure serves with great fracture-proof effectiveness and high lithium-ion diffusion rate. It has better ion permeability than solid core-shell structure but worse structural stability than shell structure. A stress surge is observed at the binding interface with an order of magnitude usually higher than that of the core-shell structure. The radial tensile stress at interface may more easily induce interfacial debonding than superficial fracture.