Enhancing electrochemical performance of nickel-rich NCM cathode material through Nb modification across a wide temperature range

LiNixCoyMn1-x-yO2 (NCM, x ≥ 0.6) possessing a high nickel content is a favorable cathode candidate for next-generation lithium-ion batteries (LIBs) owing to its ultra-high energy density. However, its sluggish electrochemical kinetics at low temperatures and severe structure destruction at high temperatures limit its practical application. This study presents a facile surface modification strategy based on niobium (Nb) to achieve LiNbO3 coating and Nb5+ doping, which can address both problems under extreme temperatures (-30-50 °C). More specifically, the LiNbO3 coating layer can decrease polarization and charge transfer resistance and enhance the structural stability of nickel-rich NCM (LiNi0·83Co0·12Mn0·05O2); Nb5+ dopants can widen the lithium-ion migration channels and thus improve the diffusion kinetics. The Nb-modified NCM (Nb-NCM) exhibits a high discharge specific capacity at subzero temperatures and excellent stability throughout the temperature range. To further evaluate the practical application potential of the Nb-NCM electrode, full cells are fabricated and tested using the Nb-NCM as a cathode and Li4Ti5O12 (LTO) as an anode. Encouragingly, the full cell also shows excellent electrochemical performance between −30 and 50 °C. These findings provide a facile and scalable strategy to enhance the electrochemical performance of nickel-rich NCM across a broad temperature range.