Synergistic interfacial engineering and microstructure regulation toward mechanically robust and long-cycling nickel-rich single-crystal cathodes for lithium-ion batteries

ithium-ion batteries derived from single-crystal LiNi$_x$Co$_y$Mn$_z$O$_2$(x ≥ 0.8, y ≤ 0.2, x + y + z = 1) cathode materials are gaining growing attention owing to their enhanced structural stability and reliable safety in comparison with polycrystalline NCM. However, the sluggish kinetic behavior, interfacial side reactions, and intragranular cracking remain major bottlenecks restricting their widespread applications. In this work, the particle size was modulated and the composite coating layer was deposited on the single-crystal LiNi$_{0.83}$Co$_{0.12}$Mn$_{0.05}$O$_2$ by introducing W and B in the multi-step calcination process, aiming to simultaneously enhance the Li$^+$ kinetics and structural stability. Notably, the as-obtained modified single-crystal LNCM-WWB cathode exhibited excellent capacity retention (93.67 % after 100 cycles, 1 C) and rate performance (144.7 mAh g$^{−1}$, 5 C) with Li metal anode. Furthermore, the LNCM-WWB/graphite pouch-type full cell achieved a capacity retention of 84.45 % after 2000 cycles. Comprehensive multi-scale in situ/ex situ characterizations ascertained that the improvement mechanism of W/B modification is ascribed to the synergistic contributions of boosted mechanical stability, reinforced interfacial stability, and ameliorated reaction heterogeneity. ... mehrThis study underscores the significance of an integrated optimization strategy and provides critical design guidelines for the future development of Ni-rich single-crystal cathode materials.