| Autor: |
Zuba, MJ, Grenier, A, Lebens-Higgins, Z, Fajardo, GJP, Li, Y, Ha, Y, Zhou, H, Whittingham, MS, Yang, W, Meng, YS, Chapman, KW, Piper, LFJ |
| Rok vydání: |
2021 |
| Zdroj: |
ACS Energy Letters, vol 6, iss 3 |
| Popis: |
Lithium-rich NMC (LR-NMC) compounds exhibit high capacities beyond the traditional redox, but it remains unclear whether the anomalous charge compensation mechanism is due to oxidized lattice oxygen or migration-assisted Mn oxidation. We compare LR-NMC with a model Mn7+ system (KMnO4) using a combination of resonant inelastic X-ray scattering (RIXS) irradiation studies and operando X-ray absorption spectroscopy/X-ray diffraction (XAS/XRD) to quantify transition metal (TM) migration, Mn oxidization, and beam-induced effects. We reveal how for KMnO4 it is possible to observe beam-induced Mn reduction resulting in trapped molecular oxygen. For LR-NMC, we observe negligible evidence for Mn oxidation while stabilized tetrahedral sites correlate more with a reduced TM environment. Finally, the additional spectroscopic structures observed in oxidized oxygen RIXS for LR-NMC are absent for gas-phase molecular oxygen. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
