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Origins and Importance of Intragranular Cracking in Layered Lithium Transition Metal Oxide Cathodes

Published version
Peer-reviewed

Repository DOI


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Authors

paragon-plus: 6857922 
paragon-plus: 4045214 
Vullum, Per Erik; paragon-plus: 847083 
Lai, May Ching; paragon-plus: 6858055 
Mahadevegowda, Amoghavarsha; paragon-plus: 6530452 

Abstract

Li-ion batteries have a pivotal role in the transition toward electric transportation. Ni-rich layered transition metal oxide (LTMO) cathode materials promise high specific capacity and lower cost but exhibit faster degradation compared with lower Ni alternatives. Here, we employ high-resolution electron microscopy and spectroscopy techniques to investigate the nanoscale origins and impact on performance of intragranular cracking (within primary crystals) in Ni-rich LTMOs. We find that intragranular cracking is widespread in charged specimens early in cycle life but uncommon in discharged samples even after cycling. The distribution of intragranular cracking is highly inhomogeneous. We conclude that intragranular cracking is caused by local stresses that can have several independent sources: neighboring particle anisotropic expansion/contraction, Li- and TM-inhomogeneities at the primary and secondary particle levels, and interfacing of electrochemically active and inactive phases. Our results suggest that intragranular cracks can manifest at different points of life of the cathode and can potentially lead to capacity fade and impedance rise of LTMO cathodes through plane gliding and particle detachment that lead to exposure of additional surfaces to the electrolyte and loss of electrical contact.

Description

Publication status: Published

Keywords

cathodes, Li-ion batteries, electron energy loss spectroscopy, electron microscopy, electrochemistry

Journal Title

ACS Applied Energy Materials

Conference Name

Journal ISSN

2574-0962
2574-0962

Volume Title

7

Publisher

American Chemical Society
Sponsorship
Horizon 2020 Framework Programme (823717)
Henry Royce Institute (EP/P024947/1)
Faraday Institution (FIRG001)
Faraday Institution (FIRG024)
Engineering and Physical Sciences Research Council (EP/L015978/1)
Cambridge Trust (NA)
Norges Forskningsr?d (197405)