Degradation Mechanisms and Mitigation Strategies of Nickel-Rich NMC-Based Lithium-Ion Batteries

Abstract

The demand for lithium-ion batteries (LIBs) with high mass-specific capacities, high rate capabilities and long-term cyclabilities is driving the research and development of LIBs with nickel-rich NMC (LiNi x Mn y Co 1−x−y O 2 , x ⩾ 0.5 ) cathodes and graphite (Li x C 6 ) anodes. Based on this, this review will summarize recently reported and widely recognized studies of the degradation mechanisms of Ni-rich NMC cathodes and graphite anodes. And with a broad collection of proposed mechanisms on both atomic and micrometer scales, this review can supplement previous degradation studies of Ni-rich NMC batteries. In addition, this review will categorize advanced mitigation strategies for both electrodes based on different modifications in which Ni-rich NMC cathode improvement strategies involve dopants, gradient layers, surface coatings, carbon matrixes and advanced synthesis methods, whereas graphite anode improvement strategies involve surface coatings, charge/discharge protocols and electrolyte volume estimations. Electrolyte components that can facilitate the stabilization of anodic solid electrolyte interfaces are also reviewed, and trade-offs between modification techniques as well as controversies are discussed for a deeper understanding of the mitigation strategies of Ni-rich NMC/graphite LIBs. Furthermore, this review will present various physical and electrochemical diagnostic tools that are vital in the elucidation of degradation mechanisms during operation to supplement future degradation studies. Finally, this review will summarize current research focuses and propose future research directions.

On the Sensitivity of the Ni-rich Layered Cathode Materials for Li-ion Batteries to the Different Calcination Conditions

“…Nickel ions are easily translocated from 3b sites to 3a sites due to the significant similarity of Ni 2+ (0.69 Å) to Li + (0.76 Å) ions. According to literature reports [ 19 , 59 , 60 , 61 ], this phenomenon causes a serious decline in capacity and reduced mobility of Li + ions. It is also postulated that there is then a change in the crystallographic structure from layered by spinel into a NiO-like rock salt phase [ 19 , 26 , 62 , 63 ].…”

Degradation and Aging Routes of Ni-Rich Cathode Based Li-Ion Batteries

“…Among the principal cations in Ni-rich cathode materials, i.e., Ni 2+ , Co 2+ , and Mn 2+ , Ni 2+ ions have the strongest propensity to mix with Li + ions (Figure 4), which results in the reduction of both capacity and Li mobility (thus conductivity) and at the same time transforming the layered over spinel crystal to NiO-like rock salt phase, both during preparation and application [43][44][45][46]. The mixing tendency is assumed to be favored from the similarity in the ionic radius of Ni 2+ (0.69 Å) and Li + (0.76 Å) [47,48].…”

Surface-Coated LiNi0.8Co0.1Mn0.1O2 (NCM811) Cathode Materials by Al2O3, ZrO2, and Li2O-2B2O3 Thin-Layers for Improving the Performance of Lithium Ion Batteries

“…Furthermore, during the charging process, the lowvalence nickel ion in the transition metal (Co, Mn) layer can migrate to the lithium layer, occupying the lithium vacancies, affecting the diffusion of Li + . The voltage stability of the material is also relatively weak, which is easy to decline rapidly (Noh et al, 2013;Li et al, 2019;Zhang et al, 2019). (2) Poor thermal stability.…”