Long-Lasting Ni-Rich NCMA Cathodes via Simultaneous Microstructural Refinement and Surface Modification

Abstract

z ]O 2 (NCMA) cathodes have attracted public attention owing to their improved durability by leveraging the advantages of NCM and NCA cathodes. As the Ni content approaches 90%, however, it is challenging to realize high-energy Ni-rich NCMA cathodes without sacrificing durability. Herein, we improve the cycling stability of a Ni-rich Li[Ni 0.93 Co 0.03 Mn 0.03 Al 0.01 ]O 2 (NCMA93) cathode using a combination strategy involving microstructural refinement and surface modification. The F-coating-induced protective layer of the Fcoated, Sb-doped NCMA93 cathode combined with its engineered microstructure enables the formation of a robust cathode−electrolyte interphase (CEI) layer on the cathode surface, which suppresses surface degradation to afford a long battery life. However, the F coating alone does not significantly improve the cycling stability of cathode because it suffers severe microcracking during cycling owing to its suboptimal microstructure. To realize a cathode with a long lifespan, a robust CEI layer should be generated and maintained on the cathode without severe microcracking.

Multiscale Crystal Field Effect for High-Performance Ultrahigh-Ni Layered Cathode

“…X-ray photoelectron spectroscopy (XPS) was adopted to explore the induced surface chemical composition evolution with Sb introduction. Figure d exhibits the Sb 3d 3/2 /O1s spectra of both samples, where 1Sb-NCA shows a weakened Li 2 CO 3 peak (≈532 eV) and a intensified lattice O peak (≈529 eV), corresponding to a new peak of Sb–O (≈539.5 eV) compared with those of NCA, suggesting the construction of a Li 7 SbO 6 layer along with the consumption of residual Li compounds. , …”

Enhancing the Integral Structural and Thermal Stability of Ultrahigh-Ni Cathodes via Morphology Refinement and In Situ Interfacial Engineering

“…The morphology SEM images of all samples are presented in Figure and Figure S3. The particle appearance of NCM-F is hardly distinct compared with the original materials, while the nanosized primary particles of NCM-W are refined in aspect ratio for obtaining a radially orderly structure. , In Figure a–e, the secondary particles of NCM-WF consist of thinner primary particles. Compared with the clean surface of NCM, NCM-WF2 is slightly rough and blurred, which is probably associated with the coating layer.…”

“…Electric vehicles (EVs) driven by repeated rechargeable batteries have attracted much attention with the nonrenewable resources’ exhaustion. , The growing demands of driving range continuously push layered cathode materials, especially LiNi x Co y Mn 1– x – y O 2 delivering a theoretical specific capacity of about 274 mAh·g –1 , into development toward a higher nickel content ( x ≥ 0.8). − Nevertheless, high-nickel cathodes easily suffer from deterioration of electrochemical performance and chemomechanical properties during extended cycling. − This recession of the polycrystalline materials is reflected in the propagation of intergranular cracks in the secondary particles during the charge and discharge process, resulting in that the electrolyte dissolves the transition metal ions along a newborn surface from the outside to the bulk and integral structural stability declines. , …”

Atomic-level insights into the first cycle irreversible capacity loss of Ni-rich layered cathodes for Li-ion batteries

“…Microstructure modifications are achieved, through boron (B) doping, 58,62,63 while the synergistic effects of suitable coatings involving zirconium (Zr) were also explored. 39 Additionally, dopants such as aluminium (Al), 64 cerium (Ce), 65 tin (Sn), 59 antimony, 66 niobium (Nb), 67 tantalum (Ta), 68 tungsten (W) 57,60 and molybdenum 19,33,36,69,70 were employed to stabilize the bulk structure by reducing internal strain, mitigating the formation of detrimental microcracks and inhibiting the growth or consolidation of primary particles. The incorporation of these elements results in an improved structural stability of NCMs, consequently elevating the overall electrochemical behavior of the associated electrodes.…”