The polarization was particularly pronounced for LNRO because of its relatively large particle size.
Fundamental understanding of anionic oxygen redox is of critical importance to propose effective material design strategy to develop novel materials that harness active oxygen redox.We believe these findings will provide additional insights into the complex oxygen redox mechanism and development of advanced high-capacity Li-ion cathodes.Moreover, this work demonstrates an explicit example of the employment of resonant inelastic X-ray scattering (RIXS) technique in understanding solid-state oxygen redox processes for energy storage and conversion applications., henceforth denoted as LNMO and LNRO, respectively, were synthesized by conventional solid-state reaction method.The first cycle voltage profile of a LNMO and b LNRO; differential capacity (d Q/d V) plot of c LNMO and d LNRO.Cells were cycled between 4.8 and 2.0 V at a current density of 5 m A g Despite this similarity, these two compounds exhibited noticeably different charge characteristics.The first cycle voltage profiles and gas evolution rates of a LNMO and b LNRO.
The total active cathode material used for the measurement was 32.9 mg LNMO (387 μmol) and 28.6 mg LNRO (253 μmol).
This difference was even more pronounced in the differential capacity (d Q/d V) plots (Fig. The charge profile of LNMO was characterized by a strong anodic peak at 4.55 V, corresponding to the extended voltage plateau, as well as two weak anodic peaks around 3.8 and 4.1 V.
In comparison, the strong anodic peak in the high-voltage region was absent in the charge profile of LNRO (Fig.
Rietveld refinement results suggest the as-produced LNMO and LNRO samples fit the structural model of monoclinic solid solution, though the nanocomposite concept concerning the mixture of layered Li Ni O (LNRO).
a Synchrotron XRD patterns, showing a similar crystal structure between these two compounds; XRD Rietveld refinement of b LNMO based on monoclinic C2/m and c LNRO based on monoclinic C2/c; d scanning electron microscopy (SEM) image of LNMO, the scale bar is 1 μm; e, f high-resolution transmission electron microscopy (HRTEM) images of LNMO with fast Fourier transform (FTT) of the selected area, the scale bar in (e) and (f) is 50 and 5 nm, respectively; g electron diffraction (ED) pattern for LNMO; h SEM image of LNRO, the scale bar is 1 μm; i, j HRTEM images of LNRO with FTT of the selected area, the scale bar in (i) and (j) is 100 and 2 nm, respectively; k ED pattern for LNROScanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) were used to further verify the morphology and crystal structure.
Recent research has explored combining conventional transition-metal redox with anionic lattice oxygen redox as a new and exciting direction to search for high-capacity lithium-ion cathodes.