Overall, both exhibited a similar morphology, composed of agglomerated primary particles, as observed in SEM images (Fig. A number of particles were examined using HRTEM and representative images are shown in Fig. The LNMO sample has a slightly smaller primary particle size than the LNRO sample, both being a few hundred nanometers.
They both exhibit a well-defined layered structure with a thin layer (~1.5 nm) of spinel and/or rocksalt phase on the surface.
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).
In this work, we aim to probe the electrochemical activity of anionic oxygen in Li-rich layered oxides by focusing on the effect of transition-metal species, Mn and Ru, representing 3d and 4d TM, on the oxygen redox process.
Both Li-rich layered oxides, Li (TM = Mn, Ru), possess a similar crystal structure and enable a similar amount of Li removal and uptake during the charge–discharge process, but with significantly different charge profiles characterized by the existence of a voltage plateau at 4.55 V in the Mn-based material, but not the Ru-based one.
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.Therefore, a similar crystal structure and morphology between the two samples was confirmed using combined synchrotron XRD, TEM, and SEM techniques. Of note, the last 0.2 Li was not removed from both compounds in this study, additional studies regarding the reversible extraction of the final 0.2 Li are needed to understand the origin of this limitation (outside the scope of this study).First charge–discharge characteristics of LNMO and LNRO.Here, we perform a comprehensive study to capture the oxygen activity, which could range from O gassing, by combining a suite of soft X-ray spectroscopy techniques with in situ differential electrochemical spectrometry (DEMS).We observe completely different oxygen behavior in the two materials, the sharp contrast between them providing strong experimental evidence for a particularly large reversible anionic oxygen redox observed in the Mn-based material, but not the Ru-based one.
Search for and elucidating:
This work provides additional insights into the complex mechanism of oxygen redox and development of advanced high-capacity lithium-ion cathodes. described two separate mechanisms for lattice oxygen participation during electrochemical cycling: irreversible oxygen loss at the surface and reversible redox of lattice oxygen within the bulk.