Fig. 4. (a) CV curves of HC‖Na half cells for dilute 1NaFSI-6TEP, HCE, DHCE-PhCF3, and DHCE-1,4-Ph(CF3)2. (b) Enlarged CV curves for the region marked using the rectangle in (a). XPS spectra of selected elements of the SEIs on HC anodes after the first cycle in the studied electrolytes: (c) P 2p, (d) N 1s, and (e) S 2p.
