A solid-state synthesis route was used to obtain DRX Li1.22Ru0.61Ni0.16O2 and Li1.22Ru0.61Na0.05Ni0.10O2 hereafter denoted as 1 and 2, respectively. The bulk composition was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES), closely following the theoretical composition (Table and Experimental Section). The crystal structure determined using high-power powder X-ray diffraction (HP-PXRD) reveals that the most characteristic XRD peaks (Figure ) in both cathodes are assigned to the C2/c space group of Li2RuO3. The merged peaks ~63° indicate disordered structures of the synthesized cathodes. Compared to 1, the XRD patterns of 2 show the asymmetric peak broadening effect (marked by the green circle in Figure ), a signature of lattice defects/strains/dislocation possibly arising from slightly larger radii of Na + doped in Li slab. Doping-induced lattice defects are expected to enhance electrochemical performances. To elucidate the electronic structures, the core-level XPS data were obtained. The XPS peak fitting data (Figure and Supplementary Discussion S1) reveal that Na doping brought significant changes in electronic structure. Before moving to the discussion of XPS peak fitting, we disclose the BE of Na. The BE value of ~1071.38 eV (Figure ) corresponds to Na + states of Na, indicating that Na has been electro-positively doped in the crystal framework. The Ni 2p (Figure and S1a) possesses two spin-orbit doublets at 855.28 (Ni 2p3/2) and 872.48 eV (Ni 2p1/2) accompanied by two satellites at 861.28 and 879.68 eV. The BE ~ 855.28 eV corresponds to Ni 3+ , whereas deconvolution of Ni 2p1/2 reveals two sets of energy band: 872.48 eV and 873.88 eV for OH -/OOH. This XPS revelation of Ni hints toward the presence of more Ni 3+ species favoring the electrophilicity of adsorbed O, thereby catalyzing the formation of -OOH species from OH -(these steps are considered as rate-determining steps in alkaline media). The electronic structure of Ru in 2 is also different from 1 (Figure ). The Ru 3d5/2 can only be fitted with a doublet (separated by~1 eV), indicating the presence of both metallic (280.68 eV) and oxidized ruthenium on surface (Figure ). This oxidized ruthenium can be inferred as oxides with low BE (281.98 eV) and with high BE (283.78 eV). The BEs at 285.38 and 286.68 eV correspond to RuOx/Ru. Most importantly, XPS results of the O 1s core-level (Figure ), fitted with three components apportioned as oxidative oxygen (O2 2-/O -: BE ~529.58 eV), carbonate/hydroxides/oxyhydroxides species (CO3 2-/OH -/OOH: BE ~531.48 eV), and absorbed water (H2O: BE ~534.88 eV) suggest a relatively more significant number of O2 2-/O-species in 2. This indicates a surplus amount of surface oxygen vacancies compared to 1 (Figure ) with hydroxides (BE ~531.7 eV) and oxygen species (BE ~533.4 eV). Firstly, Na doping has significantly modified the electronic structure, which agrees with previous reports on layered cathodes. Secondly, the excess of O2 2-/O-species on the surface of 2 is beneficial for catalyzing OER reactions in alkaline media. 21 Scanning electron microscopy (SEM) images reveal a distinguishable feature in their morphology (Figure and Supplementary Discussion S2). The particles in 2 show cornered-shaped structures with smaller particles decorating larger particles, thus creating rougher surfaces. These rough surfaces expose multiple active sites facilitating oxygen evolution reactions. A better sintering ability with enhanced particle connectivity is an additional feature brought by Na doping. The lattice fringe distance of 0.475 nm revealed under high-resolution transmission electron microscopy (HRTEM) image corresponds to the disordered structure (Figure ). As expected Na + (marked by the pink arrow) distributes uniformly inside the lattice (Figure ). Few other exciting features that promote OER kinetics can be explored under HRTEM. For instance, defective zones (marked by the yellow arrow) can also be seen in Figure of Na-DRX, whereas no such beneficial features can be seen in 1 (Figure ). These defective zones are termed as stacking fault defects, primarily arising from the differences in ionic radii of Na + and Li + . These defective sites can modulate the electronic structure and tune surface properties of 2, thus optimizing the adsorption energies of OER steps. The autocorrelated image reveals the Na-doping and defects zone (Figure ).