Abstract
In recent years, cobalt has become a critical constraint on the supply chain of the Li‐ion battery industry. With the ever‐increasing projections for electric vehicles, the dependency of current Li‐ion batteries on the ever‐fluctuating cobalt prices poses serious environmental and sustainability issues. To address these challenges, a new class of cobalt‐free materials with general formula of LiNix Fey Alz O2 (x + y + z = 1), termed as the lithium iron aluminum nickelate (NFA) class of cathodes, is introduced. These cobalt‐free materials are synthesized using the sol–gel process to explore their compositional landscape by varying aluminum and iron. These NFA variants are characterized using electron microscopy, neutron and X‐ray diffraction, and Mössbauer and X‐ray photoelectron spectroscopy to investigate their morphological, physical, and crystal‐structure properties. Operando experiments by X‐ray diffraction, Mössbauer spectroscopy, and galvanostatic intermittent titration have been also used to study the crystallographic transitions, electrochemical activity, and Li‐ion diffusivity upon lithium removal and uptake in the NFA cathodes. NFA compositions yield specific capacities of ≈200 mAh g−1, demonstrating reasonable rate capability and cycling stability with ≈80% capacity retention after 100 charge/discharge cycles. While this is an early stage of research, the potential that these cathodes could have as viable candidates in next‐generation cobalt‐free lithium‐ion batteries is highlighted here.
