Nickel-Rich and Cobalt-Free Layered Oxide Cathodes for Lithium Ion Batteries: A Perspective Solution for Future

Abstract

Recently, the electric vehicle market has attracted significant global attention with the advent of lithium-ion batteries (LIBs) with nickel-rich layered oxidecathodes paired with graphite/silicon anodes. However, the presence of cobalt in LixNi1-y-zCoyMnzO2(NCM-type) cathodes triggersseveralchallenges,including high cost, toxicity, and limited geographical reserve, exacerbatingthe global supply chain.Therefore, battery manufacturers worldwide are trying to eliminate the dependency on cobalt while synthesizing oxide cathodes.In this perspective,we proposeanew class of layered oxide cathodes-LixNi0.8M0.1Mn0.1O2 (NMM811) for LIBs synthesized using thecitrate-nitrate route that arecobalt-free and nickel-rich. Powder X-ray diffraction (PXRD) and Rietveld refinement coupled with electrochemical characterizations, including cyclic voltammetry and galvanostatic charge/discharge,illustrate that multivalent cations (Mn+) could be a suitable alternative to replace cobalt suppressing Li/Ni cation mixing, a perennial problem in NCM-type cathodes. Synchrotron-basedXRD,XPS and XANES spectra reveal the state of phases and extent of Li+/Ni2+cation mixing in the cathode by revealing the material's surface chemical composition and geometric information. We also examinethe electronic structure and valence states through band structure, the density of states, and Bader charge analysisusing density functional theory. Electrochemical measurements revealed the initial discharge capacity of the Co-free NMM811 cathode is ~198 mAh g-1within the voltage range of 3.0-4.5 V at 0.1C. This study opens a new possibilityfor developingNi-rich NMM811 akin to NCM811 in terms of performance.