Modeling of the multi-cycle deep charge and discharge attenuation mechanism of non-aqueous Li–O2 batteries

Abstract

Due to the high energy density, non-aqueous lithium-oxygen (Li–O2) batteries attract significant attention. However, batteries' high capacity attenuation rate under deep charge and discharge conditions remains a significant challenge. This paper presents a multi-cycle deep charge and discharge model for non-aqueous lithium-oxygen batteries, which predicts the performance of the battery during multiple deep charge and discharge cycles at high and low discharge-specific capacities. The parameter states during different discharge stages in different discharge cycles are investigated by analyzing the battery's cathode porosity, product volume fraction, and oxygen concentration changes. The study shows that as the number of cycles increases, the deposition of a small number of discharge products in the cathode altered the distribution of the newly generated products, thereby affecting the cathode structure and oxygen transport in the subsequent discharge. Moreover, depositing a small amount of discharge products can result in significant capacity attenuation in the battery. This model can accurately evaluate the deep charge and discharge performance attenuation process of non-aqueous Li–O2 batteries, which helps improve the understanding of the deep discharge attenuation mechanism of non-aqueous Li–O2 batteries.