Nano-structural changes in Li-ion battery cathodes during cycling revealed by FIB-SEM serial sectioning tomography

Bohang Song, Tan Sui, Siqi Ying, Liu Li, Li Lu, Alexander M. Korsunsky

Research output: Contribution to journalArticlepeer-review

60 Citations (Scopus)

Abstract

The growing demand for reliable, durable electrical energy systems to power electric and hybrid vehicles motivates worldwide efforts aimed at developing high-energy, high-power density batteries. One of the obstacles to widespread industry adoption is the lack of profound understanding and the ability to monitor and control the long-term degradation and capacity fading observed in these systems. Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM) serial sectioning is used to reconstruct the evolution of the three-dimensional structure of Li-ion battery electrodes during extended cycling. High resolution imaging reveals microstructural information at the level of the composite framework consisting of the spheroidal micro-particles of the active material held together by the polymer matrix. The evolution of damage within the micro-particles of the active material can be seen in the form of voiding, cracking and ultimate fragmentation. In particular, when spherical micro-particles of Li-rich layered oxides are used as the cathode, it is found that the extent of fragmentation varied in the direction of Li+ diffusion current from the particle surface inwards. We use a simple model of the strain and strain gradient effects of Li+ transient diffusion within the electrode to identify the driving force for particle fragmentation, and discuss the implication of these results.

Original languageEnglish
Pages (from-to)18171-18179
Number of pages9
JournalJournal of Materials Chemistry A
Volume3
Issue number35
DOIs
Publication statusPublished - 27 Jul 2015
Externally publishedYes

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