• • NCM-60 delivers 157.28 mA·h/g at 1C with 55.06% retention after 200 cycles, whereas polycrystalline NCM suffers rapid capacity decay due to intergranular cracking; this 55.06% retention, though moderate, represents a substantial improvement over baseline polycrystalline materials, directly addressing the structural collapse bottleneck in high-nickel cathodes.
• • Cross-sectional SEM confirms zero apparent cracks in NCM-60 after 200 cycles, while PC-NCM shows severe intergranular fracture; this eliminates the primary failure mode that limits cycle life in electric vehicle batteries, potentially extending pack warranty and reducing replacement costs.
• • Optimal solvothermal time is 60 min; shorter times reduce precursor particle size and crystallinity, degrading electrochemical performance. This narrow processing window (60 min) imposes strict scalability requirements but enables consistent single-crystal morphology.
• • Pre-oxidation of the carbonate precursor before LiOH mixing reduces CO2 generation during sintering, lowering lithium–nickel disorder; this step is critical for achieving high crystallinity and phase purity (R-3m space group) in the final single-crystal NCM811.