Overcharge-Induced Phase Heterogeneity and Resultant Twin-Like Layer Deformation in Lithium Cobalt Oxide Cathode for Lithium-Ion Batteries

Juhyun Oh, Seung Yong Lee, Hwangsun Kim, Jinseok Ryu, Byeongjun Gil, Jongki Lee, Miyoung Kim

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Overcharging is expected to be one of the solutions to overcome the current energy density limitation of lithium-ion battery cathodes, which will support the rapid growth of the battery market. However, high-voltage charging often poses a major safety threat including fatal incendiary incidents, limiting further application. Numerous researches are dedicated to the disadvantages of the overcharging process; nonetheless, the urgent demand for addressing failure mechanisms is still unfulfilled. Herein, it is revealed that overcharging induces phase heterogeneity into layered and cobalt oxide phases, and consequent “twin-like deformation” in lithium cobalt oxide. The interplay between the uncommon cobalt(III) oxide and the deformation is investigated by revealing the atomistic formation mechanism. Most importantly, abnormal cracking is discovered in the vicinity of the cobalt oxide where structural instability induces substantial contraction. In addition, surface degradation is widely observed in the crack boundary inside the particle. As unintentional overcharging can occur due to local imbalance in state-of-charge in severe operating conditions such as fast charging, the issues on overcharging should be emphasized to large extent and this study provides fundamental knowledge of overcharge by elucidating the crack development mechanism of layered cathodes, which is expected to broaden the horizon into high voltage operation.

Original languageEnglish
Article number2203639
JournalAdvanced Science
Volume9
Issue number32
DOIs
StatePublished - Nov 14 2022
Externally publishedYes

Keywords

  • layered lithium transition-metal oxides
  • lithium-ion batteries
  • mechanical cracks
  • overcharge
  • transmission electron microscopy

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