Fig. 4: Interfacial compatibility in ASSNIB.
From: A family of dual-anion-based sodium superionic conductors for all-solid-state sodium-ion batteries
a,b, Scanning electron microscopy images of the NHOC-based cathode composite (a) and the interphase between the cathode composite and NHOC electrolyte layer (b). c,d, Ex situ Hf 4f (c) and Cl 2p (d) X-ray photoelectron spectra of cathode composites at different charge–discharge states, that is, the initial state, fully charged to 4 V (C-4V), fully discharged to 2 V (D-2V), after three cycles and after five cycles at 0.2 C. The spin doublet components are shaded with the same colour for each spectrum. e, Intermittent galvanostatic voltage profile of NHOC-based ASSNIB in the initial three cycles. The ASSNIB was cycled at 20 mA g−1, and each impedance spectrum was recorded after a rest period of 1 h to allow for reaching equilibrium. The time (h) here represent only the charging and discharging time, excluding any resting periods. f, Distribution of relaxation times spectra calculated from EIS measurements. The τ represents relaxation time, and γ (τ) stands for distribution function of relaxation times. g, Two-dimensional intensity colour map of the charge- and discharge-dependent distribution of relaxation times curves abstracted from f.
