Thermally-driven mesopore formation and oxygen release in delithiated NCA cathode particles

Thermally-driven mesopore formation and oxygen release in delithiated NCA cathode particles

TitleThermally-driven mesopore formation and oxygen release in delithiated NCA cathode particles
Publication TypeJournal Article
Year of Publication2019
AuthorsMünir M Besli, Alpesh K Shukla, Chenxi Wei, Michael Metzger, Judith Alvarado, Julian Boell, Dennis Nordlund, Gerhard Schneider, Sondra Hellstrom, Christina Johnston, Jake Christensen, Marca M Doeff, Yijin Liu, Saravanan Kuppan
JournalJournal of Materials Chemistry A
Volume7
Issue20
Pagination12593 - 12603
Date Published04/2019
ISSN2050-7488
Abstract

The structural integrity of layered Ni-rich oxide cathode materials is one of the most essential factors that critically affect the performance and reliability of lithium-ion batteries. Prolonged battery operation often involves repeated phase transitions, buildup of mechanical stresses, and could provoke thermal spikes. Such sophisticated chemo-thermo-mechanical interplay can cause performance degradation through structural disintegration of the cathode active materials (CAMs). Herein, we systematically investigate the thermal decomposition, fracture, and oxygen evolution of chemically delithiated Li0.3Ni0.8Co0.15Al0.05O2 (NCA) particles upon heating from 25°C to 450°C using a number of advanced X-ray and electron probes. We observed a continuous reduction of the Ni oxidation state upon heating, as well as the release of oxygen from the NCA lattice that undergoes the thermally induced phase transformations. The release of oxygen also created numerous mesopores throughout the analyzed particles, which could significantly affect the chemical and mechanical properties of the electrode. In addition, intergranular and intragranular fracturing at elevated temperatures also contribute to the degradation of the NCA cathode under these conditions. Our investigation of the mechanical integrity at elevated temperatures provides a fundamental understanding of the thermally driven chemomechanical breakdown of the NCA cathode active materials.

DOI10.1039/C9TA01720H
Short TitleJ. Mater. Chem. A
Refereed DesignationRefereed