Development of Nickel-Rich and Cobalt-Free Layered Oxide Cathode - A Prospective Solution to The Battery Industry's Cobalt Problem

Abstract

In recent years, the electric vehicle market has attracted significant global attention due to the emergence of lithium-ion batteries (LIBs) with nickel-rich layered oxide cathodes (NCM) paired with graphite/silicon anodes. However, the presence of cobalt in LixNi1-y-zCoyMnzO2 (NCM) cathodes has become an issue for battery suppliers and industries worldwide due to the limited cobalt reserve with geographical constraint exacerbate with rapid price fluctuation affecting the global supply chain. Herein, we propose a new class of cobalt-free and nickel-rich layered oxide cathode-LixNi0.8M0.1Mn0.1O2 (NMM811) prepared using the citrate-nitrate route as an alternative to NCM-based cathodes for LIBs. Powder X-ray diffraction (PXRD) and Rietveld refinement coupled with electrochemical characterizations, including cyclic voltammetry and galvanostatic charge/discharge in a 2032 type coin cell of the pristine/cycled electrodes illustrate that multivalent cations (Mn+) could be a suitable alternative to replace cobalt for suppressing Li/Ni cation mixing. The XPS and XANES spectra using synchrotron radiation show the surface chemical composition and geometric information of cathode material, respectively, revealing the state of phases and extent of Li + /Ni 2+ cation mixing. We also study the electronic structure and valence states using density functional theory (DFT). Electrochemical measurements revealed the initial discharge capacity of the Co-free NMM811 cathode ~198 mAhg -1 within the voltage range of 3.0-4.5 V at 0.1C. This study opens a new possibility for the development of Ni-rich NMM811 akin to NCM811 in terms of performance for high voltage LIBs cathodes.