Multiscale Crystal Field Effect for High-Performance Ultrahigh-Ni Layered Cathode

Further popularization of ultrahigh-Ni layered cathodesfor high-energylithium-ion batteries (LIBs) is hampered by their grievous structuraland interfacial degeneration upon cycling. Herein, by leveraging thestrong electronegativity and low solubility properties of Sb element,a multifunctional modification that couples atomic/microstructuralreconstruction with interfacial shielding is well designed to improvethe LiNi0.94Co0.04Al0.02O2 (NCA) cathode by combining Sb5+ doping and Li7SbO6 coating. Notably, a robust O framework is establishedby regulating local O coordination owing to the incorporation of astrong Sb-O covalence bond, leading to the inhibited latticeO evolution at high voltage, as revealed by synchrotron X-ray absorptionspectroscopy. Moreover, the radially aligned primary particles with(003) crystallographic texture and refined/elongated sizes are achievedby the pinning of Sb on grain boundaries and are confirmed by scanningtransmission electron microscopy, resulting in the fast Li+ diffusion and mitigated particle cracking. Additionally, in situ construction of the Li7SbO6 ionic conductive layer on grain boundaries can effectively boostinterfacial stability and Li+ kinetics. As a result, theoptimal Sb-modified NCA delivers a high capacity retention of 94.6%after 200 cycles at 1 C and a good rate capacity of 183.9 mAh g(-1) at 10 C, which is expected to be applied to next-generationadvanced LIBs.

Automated summary

This study presents a multifunctional modification method for improving the performance of LiNi0.94Co0.04Al0.02O2 (NCA) cathode, by leveraging the strong electronegativity and low solubility properties of Sb element. The modification involves Sb-doping and Li7SbO6 coating, which leads to atomic/microstructural reconstruction and interfacial shielding, resulting in improved stability and lithium ion diffusion kinetics.