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The article focuses on a study which examines the potential of sodium or Na+/vacancy disordering in improving the cycling stability, kinetics and capability of Na-ion batteries (NIBs). The study involved methods including the synthesis of P2-NaNM and P2-NaNMT compounds, electrochemistry, and density functional theory (DFT) calculations. Results are provided with information on P2-NaNM and P2-NaNMT crystal structures, electrochemical performance and charge compensation mechanism.

Electrolyte gating with ionic liquids is a powerful tool for inducing novel conducting phases in correlated insulators. An archetypal correlated material is vanadium dioxide (VO2), which is insulating only at temperatures below a characteristic phase transition temperature. We show that electrolyte gating of epitaxial thin films of VO2 suppresses the metal-to-insulator transition and stabilizes the metallic phase to temperatures below 5 kelvin, even after the ionic liquid is completely removed. We found that electrolyte gating of VO2 leads not to electrostatically induced carriers but instead to the electric field-induced creation of oxygen vacancies, with consequent migration of oxygen from the oxide film into the ionic liquid. This mechanism should be taken into account in the interpretation of ionic liquid gating experiments. [ABSTRACT FROM AUTHOR]