Single-Crystal Ni-Rich Layered LiNi_0.9Mn_0.1O₂ Enables Superior Performance of Co-Free Cathodes for Lithium-Ion Batteries

Abstract

Cobalt-free nickel-rich layered oxides are considered as promising next-generation cathode materials for lithium-ion batteries (LIBs) due to their high capacity and controllable costs. However, the inferior cycling stability makes their application questionable. Herein, polycrystalline LiNi0.9Mn0.1O2 (PC-NM91) and single crystal LiNi0.9Mn0.1O2 (SC-NM91) were prepared by mixing the precursor with LiOH·H2O (and Li2SO4·H2O for SC-NM91). SC-NM91 with complete structure, uniform morphology, and good dispersion was successfully synthesized. The initial discharge capacity and Coulombic efficiency of both samples were similar. However, the capacity retention of SC-NM91 was 85.3% after 300 cycles at 1 C, while PC-NM91 showed only 65.8% under the same conditions. The proposed SC-NM91 cathode has better cycle stability than PC-NM91, especially under severe cycle conditions (4.5 V, 2 C, and 60 °C). The enhanced performance of SC-NM91 can be ascribed to the stronger structure, which prevents intergranular cracks, surface pulverization, disordered phase transition, and interface side reactions. In addition, it has a lower degree of Li+/Ni2+ mixing and fast Li+ diffusivity. This study provides insight into the role of single crystal structure in mitigating the performance degradation of Co-free Ni-rich cathodes and reveals that SC-NM91 can be a commercially available cathode material for high-energy LIBs.

Enhancing surface‐to‐bulk stability of layered Co‐free Ni‐rich cathodes for long‐life Li‐ion batteries

“…Clearly, both samples undergo multi‐step phase transitions during delithiation: originally from hexagonal phase (H1) to monoclinic phase (M), then to hexagonal phase (H2), and finally to another hexagonal phase (H3). In the process of lithiation, the above phase transitions will happen in reverse 33 . The H2–H3 redox peaks of different cycle numbers for NMGe‐0.5 represent negligible change in peak potential and intensity (Figure 4E), whereas those of the pristine NM decay quickly, indicating the robust oxygen framework and reduced side reactions could increase the reaction reversibility.…”

Slug Flow Coprecipitation Synthesis of Uniformly-Sized Oxalate Precursor Microparticles for Improved Reproducibility and Tap Density of Li(Ni0.8Co0.1Mn0.1)O2 Cathode Materials

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Ultrafast Laser Drilling of 3D Porous Current Collectors for High-Capacity Electrodes of Rechargeable Batteries

“…Fe, Mn, V, etc.) have been developed as leading commercial cathode materials, − while graphite/carbon, Li 4 Ti 5 O 12 , and silicon/tin are the common anode materials for commercial batteries. − Innovations on a new material system (for example, high-voltage material) and new battery structure (for example, CTP battery) are lately focused on the design and development of high-performance batteries. , …”