A New Insight into the Capacity Decay Mechanism of Ni‐Rich Layered Oxide Cathode for Lithium‐Ion Batteries. Issue 47 (13th October 2022)

• Record Type: Journal Article
• Authors: Wu, Shumeng; Zhang, Xiaodong; Ma, Su; Fan, Ersha; Lin, Jiao; Chen, Renjie; Wu, Feng; Li, Li
• Is Part Of: Small. Volume 18:Issue 47(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-13
• Subjects: cathode electrolyte interphase (CEI) layer evolution -- degradation mechanisms -- H2‐H3 phase transition -- Ni‐rich cathodes; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202204613
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Understanding the mapping relationship between electrochemical characteristics and physicochemical properties of layered LiNi0.80 Co0.15 Al0.05 O2 (NCA) cathodes is important to develop high energy density lithium‐ion batteries (LIBs). Combining in situ and ex situ characterization, the effect of the H2‐H3 phase transition on the capacity decay and aging mechanism of NCA materials are systematically investigated. With the increase of cut‐off voltage, the cathode electrolyte interphase (CEI) on the NCA interface shows an evolutionary path of formation‐thickening‐rupture. This phenomenon is closely related to the H2‐H3 phase transition. The volumetric stresses and strains caused by the H2‐H3 phase transition accelerate the formation and expansion of secondary particle microcracks in the electrode material, leading to the growth of interfacial CEI variations. The capacity of the electrode material can decrease even if the material does not experience the H2‐H3 phase transition due to the persistence of interfacial side reactions with calendar aging from long cycles. This work opens up a valuable perspective for the study of the mapping relationship between phase transition and electrochemical properties in Ni‐rich layered oxide cathodes and provides guidance for developing high capacity and long cycle life LIBs. Abstract : Combining in situ and ex situ characterization, the effect of the H2‐H3 phase transition on the capacity decay mechanism of LiNi0.80 Co0.15 Al0.05 O2 (NCA) materials are systematically investigated. With the increase of cut‐off voltage, the cathode electrolyte interphase on the NCA interface shows a formation‐thickening‐rupture evolutionary path. Moreover, other effects of phase transition, including bulk failure and interfacial failure, are discussed in detail.