Interfacial Robustness and Improved Kinetics of Single-Crystal Ni-Rich Co-Free Cathodes Enabled by Surface Crystal-Facet Modulation.

Abstract

The elimination of Co from Ni-rich layered cathodes is critical to reduce the production cost and increase the energy density for sustainable development. Herein, a delicate strategy of crystal-facet modulation is designed and explored, which is achieved by simultaneous Al/W-doping into the precursors, while the surface role of the crystal-facet is intensively revealed. Unlike traditional studies on crystal structure growth along a certain direction, this work modulates the crystal-facet at the nanoscale based on the effect of W-doping dynamic migration with surface energy, successfully constructing the core-shell (003)/(104) facet surface. Compared to the (003) plane, the induced (104) facet at the surface can provide more space for Li⁺-activity, enabling lower interfacial polarization and higher Li⁺-transport rate. Additionally, bulk Al-doping is beneficial for enhancing the Li⁺-diffusion from the exterior surface to the interior lattice. With improved interfacial stability and restrained surface erosion, the product exhibits superior capacity retention and boosted rate performance under the elevated temperature.