Fig. 2: Carrier redox mechanism.
From: Reversible multivalent carrier redox exceeding intercalation capacity boundary
a GCD curves, evolution of the copper content quantified from the XPS spectra, and corresponding Cu 2p XPS data in (b), intercalation (discharging) and (c), deintercalation (charging). d XAFS data for specific discharge states and corresponding XANES region amplification. e Optical images of the CuII and CuI electrolytes and GCD curves of f-VS2 in the corresponding systems. See Methods for the configuration of the CuI electrolyte. f Cycling performance of f-VS2 using the CuI electrolyte. g Comparison of the maximum capacity and cycling lifespan of f-VS2 in the CuII and CuI electrolyte systems. h Schematic of the valence distribution of the intercalated copper ions in the discharge. Monovalent copper resulting from carrier redox appears at the beginning of intercalation, whereas divalent copper appears at the final stage of intercalation. i Schematic of the intercalation process of monovalent-ion, multivalent-ion, and multivalent-ion redox carriers. Intercalation of multivalent-ion redox carriers can improve the charge transfer capacity while occupying a limit number of transition metal (TM) redox sites.
