| Popis: |
The possibility to co intercalate sodium ions together with various glymes in graphite enables its use as a negative electrode material in sodium ion batteries SIBs . However, the storage mechanism and local interactions appearing during this reaction still needs further clarification. 1 H, 13 C and 23 Na ex situ solid state NMR ss NMR experiments are performed to obtain insights into the storage mechanism depending on the state of charge SOC and the electrolyte solvent used. Distinct differences could be seen depending on the SOC, indicating a possible change of the solvation shell, differences in the mobility as well as a phase transition at the plateau. Furthermore, exchange experiments reveal information on the sodium ion transport process in the graphitic lattice. The inferior cycling performance of triglyme 3G compared to diglyme 2G and pentaglyme 5G is also reflected in the ss NMR spectra, showing a reduced mobility and stronger interactions between sodium ions, 3G and graphite already at room temperature RT |
