Effective modulus of graphite electrode in Li-ion battery by considering ion concentration, porosity, and binding energy during lithium intercalation

A new mathematical method that considers the influences of Li-ion concentration, Li–C binding energy, and porosity simultaneously in an electrode is suggested for predicting the effective elastic modulus (EEM) of an electrode. EEMs of electrodes are significantly influenced by the porosity and ion concentration. Graphite electrodes are fabricated and tensile tests are conducted at various states of charge by constructing some pouch cells with LiMn₂O₄ cathode and graphite anode. EEM of graphite increases dramatically during Li-ions’ intercalation into the electrode, and reaches a value up to 3 times that of the uncharged electrode. The experimental results are compared with analytical predictions to validate, and the two results show good agreement with a maximum error of 8.6%.