High‐Voltage Induced Surface and Intragranular Structural Evolution of Ni‐Rich Layered Cathode. Issue 19 (11th April 2022)

• Record Type: Journal Article
• Authors: Liu, Hanshuo; Xie, Zhong; Qu, Wei; Dy, Eben; Niketic, Svetlana; Brueckner, Shawn; Tsay, Ken; Fuller, Eric; Bock, Christina; Zaker, Nafiseh; Botton, Gianluigi A.
• Is Part Of: Small. Volume 18:Issue 19(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-11
• Subjects: degradation mechanisms -- high‐voltage -- intragranular structural evolution -- lithium‐ion batteries -- Ni‐rich cathodes; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202200627
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Layered Ni‐rich lithium transition metal oxides are promising cathode materials for high‐energy‐density lithium‐ion batteries. These cathodes, however, suffer from rapid performance decay under high‐voltage operation. In this work, the electrochemical properties and structural evolution of the LiNi0.8 Mn0.1 Co0.1 O2 (NMC811) cathode upon high‐voltage cycling are investigated. The results show that the NMC811 cathode not only experiences surface evolution with the formation of Li‐deficient rock‐salt layers, but also suffers from drastic intragranular structural changes inside bulk grains after high‐voltage cycling. Direct evidence for the formation of transition‐metal/Li disordering domains with uneven Li content and lattice plane distortion at the internal grains of 4.6 V‐cycled NMC811 are provided with their atomic ordering and spatial distribution clearly resolved. The complex intragranular structural changes impede Li + diffusion inside bulk material, resulting in kinetic limitation and capacity loss. The results demonstrate that the high‐voltage cycling would induce severe structural degradation at the grain interior of the cathode material beyond surface evolution, which contributes significantly to the rapid performance decay of the NMC811 cathode. The findings provide new insights for developing effective countermeasures to mitigate this degradation pathway. Abstract : The failure mechanism of the Ni‐rich layered cathode upon high‐voltage operation is investigated in this study. The loss of active phase and sluggish kinetics due to surface evolution and intragranular structural changes are revealed to be major causes for the rapid performance decay.