Analysis of the Discharge Termination Mechanism of a Nonaqueous Li-O2 Battery Based on a Digital Reconstruction Model.

ABSTRACT

The service life of the lithium-oxygen (Li-O2) battery is an essential factor in measuring the performance of the battery, and it is also imperative to clarify the reason for battery termination. In this work, the positive electrode of a nonaqueous Li-O2 battery was selected after cutoff under different discharge conditions, and the digital reconstruction model of the positive electrode was carried out by X-CT technology. The reconstructed positive electrode's structural characteristics, material transport characteristics, and electrical conductivity were analyzed. It is found that the positive electrode has an apparent expansion phenomenon after constant capacity cyclic charge and discharge, but this situation is not evident after deep discharge. After the constant capacity test is cut off, the product distribution range in the positive electrode is more comprehensive and the material transport efficiency is higher. However, after deep discharge, the product distribution in the positive electrode is more concentrated and the material transport efficiency is lower. There are apparent differences in the termination mechanism between constant capacity cycle discharge and deep discharge. This paper provides a compelling theoretical basis for revealing the discharge termination mechanism of nonaqueous Li-O2 batteries.