Simple Synchronous Dual-Modification Strategy with Zr⁴⁺ Doping and CeO₂ Nanowelding to Stabilize Layered Ni-Rich Cathode Materials

Abstract

A Ni-rich layered oxide, one promising cathode for lithium-ion batteries (LIBs), exhibits the advantages of low cost and high capacity but suffers from rapid capacity loss due to bulk structural instability and surface side reactions. Herein, a simple synchronous dual-modification strategy with Zr4+ doping and CeO2 nanowelding is proposed to address such issues. Utilizing the migration energy difference of Zr and Ce ions in layered structures, one-step high-temperature sintering of LiNi0.8Co0.1Mn0.1O2 particles with Zr and Ce nitrate distributions enables simultaneous doping of Zr ions in the bulk and CeO2 surface modification. Therein, Zr ions in the bulk occupying the Li sites can improve the Li+ diffusion rate and stabilize the crystal structure, while CeO2 on the surface provides nanowelding between the grain boundaries and resistance to electrolyte erosion. Theoretical calculations and a series of structure/composition characterizations (i.e., neutron scattering, in situ X-ray diffraction, etc.) validated the proposed strategy and its role in stabilizing the Ni-rich cathodes. The synergistic effect of Zr4+ doping and CeO2 nanowelding enables an impressive initial capacity of 187.2 mAh g–1 (2.7–4.3 V vs Li/Li+) with 86.1% retention after 200 cycles at 1 C and rate capabilities of 146.6 and 127.3 mAh g–1 at 5 and 10 C, respectively. Upon increasing the testing temperature to 60 °C, the dual-modified Ni-rich cathode exhibits an initial discharge capacity of 203.5 mAh g–1 with a good retention of 80.8% after 100 cycles at 0.5 C. The present strategy utilizing the migration energy difference of metal ions to achieve synchronous bulk doping and surface modification will offer fresh insights to stabilize layered cathode materials for LIBs, which can be widely used in other kinds of batteries with various cathode materials.

Na Doping and CeO2 Nanoparticle Surface Modification Enhancing the Li-Rich Li1.2Mn0.54Ni0.13Co0.13O2 Cathode Material for a Lithium-Ion Battery

“…The results of the XPS measurements are shown in Figure . The characteristic Ce 3d peaks (Figure a) can be clearly observed at about 898 and 901 eV, corresponding to Ce 4+ , confirming the CeO 2 on the surface. And the characteristic peak of Na 1s (Figure b) is detected at 1071 eV, verifying the successful introduction of Na ions.…”

Enhancing the Integral Structural and Thermal Stability of Ultrahigh-Ni Cathodes via Morphology Refinement and In Situ Interfacial Engineering

“…From the perspective of dynamics, the galvanostatic intermittent titration technique (GITT) is used for testing the lithium-ion diffusion coefficient of different materials. , Figure a,b roughly expresses the same trend in the lithiation process: D Li + rises rapidly from work voltage at 3.6 V, then drops rapidly about 4.15 V, and finally keeps gently until 4.3 V, where two dramatic changes of D Li+ correspond to two phase transitions (H1 → M and H2 → H3). The overall D Li+ of the pristine sample is slightly inferior to NCM-WF2 after the first cycle, which is affected by constructed fast lithium-ion thoroughfare.…”