Nitrogen-containing additive and FEC solvent synergistically modified ion transport electrolyte interfaces for high-performance NCM811 cathodes

Nickel-rich layered oxide materials, specifically LiNi 0.8 Co 0.1 Mn 0.1 O 2 or NCM811, exhibit exceptional theoretical energy densities, rendering them highly suitable for applications demanding high energy outputs. Their superior specific capacity is a key factor contributing to this suitability. However, the unstable cathode electrolyte interphase (CEI) formed on nickel-rich materials during cycling degrades battery performance by consuming active lithium ions. Stable CEI formation is crucial for improving electrochemical stability. In this study, a novel NO 2 -functionalized methyl benzoate-containing reagent (Methyl 5-Nitro-2-Methylbenzoate MNM) was introduced into a conventional carbonate electrolyte. This combination promoted the in-situ formation of a stable, ion-conductive CEI on the NCM811 electrode. The assembled NCM811||Li battery exhibited excellent cycling stability, delivering a discharge capacity of 163.01 mAh g⁻¹ and maintaining 90.82% of its original capacity after 100 cycles at a 1 C rate. Moreover, at a higher charge/discharge rate of 7 C, the battery maintained a specific capacity of 136.70 mAh g⁻¹. X-ray photoelectron spectroscopy (XPS) analysis revealed that MNM additives enhanced the conversion of FEC into LiF and Li₃N, improving the CEI membrane’s stability and ion transport. This study presents a novel strategy for designing highly stable electrolyte systems that exhibit ion conductivity, optimized for use in applications with high energy density requirements. Graphical abstract The alternative text for this image may have been generated using AI.