Fig. 3: Electrochemical analysis of the pristine and fully cycled spinel LixCo3−xO4.
From: Navigating surface reconstruction of spinel oxides for electrochemical water oxidation
a The cyclic voltammetry (CV) curves of the pristine LixCo3−xO4. b Schematic of the surface reconstruction of spinel oxides. c The O 1 s spectra of fully cycled spinel Co3O4 and LiCo2O4. d The relative ratio of surface oxyhydroxide and lattice oxygen in the fully cycled spinel LixCo3−xO4. e The high-resolution transmission electron microscopy (HRTEM) images of the pristine and cycled spinel Co3O4 and LiCo2O4. f The estimated reconstruction degree (Dr) of spinel LixCo3−xO4. g The CV curve of the pristine and cycled spinel Co3O4 and LiCo2O4. h The experimentally measured current density (@ 1.62 V vs. RHE) of the pristine and cycled spinel LixCo3−xO4. i The plot integrating both the experimentally measured and theoretically calculated reconstruction degree. The current density (@ 1.62 V vs. RHE) change (ΔI) between cycled and pristine spinel LixCo3−xO4 is used to represent the experimentally measured reconstruction degree, while the DFT calculated metal-oxygen covalency polarity (the metal-oxygen covalency difference between MO4 and MO6, ΔC) is used to represent the theoretically predicted reconstruction degree. The insert shows the linear fitting of the two parameters.
