The results of research on the structural, transport and electrochemical properties of the NaxTi1/6Mn1/6Fe1/6Co1/6Ni1/6Cu1/6O2 high entropy oxide cathode material for Na-ion batteries are presented. Pristine high entropy oxide (HEO) O3-NaTi1/6Mn1/6Fe1/6Co1/6Ni1/6Cu1/6O2...

As the Li‐ion batteries market encounters numerous obstacles, such as not sufficient production to the demands, there is a need to develop post‐lithium technologies, such as Na‐ion batteries. Na0.67MnO2 cathode material provides high capacity; however, it suffers from phase transitions during the (de)intercalation process. Herein, it is presented that magnesium substitution in Na0.67Mg0.2Mn0.8O2 stabilizes the crystal structure during cycling, which was confirmed by operando X‐ray diffraction measurements as well as the long‐term cycling experiment. It also enhances the electronic conductivity from 9 × 10−6 to 7 × 10−5 S cm−1 and the ionic one from 3 × 10−6 to 4 × 10−5 S cm−1. X‐ray absorption spectroscopy O K‐edge spectra are in line with the enormous exceeding of the theoretical capacity of Na/Na+/NaxMg0.2Mn0.8O2 cell (nonreversible discharge capacity of 310 with 155 mAh g−1 of theoretical capacity). Electronic structure calculations performed by the Korringa–Kohn–Rostoker method in the framework of local spin‐density approximation + U in ordered Na2/3Mg1/3Mn2/3O2 approximant support its semiconducting properties as well as confirm that substitution of Mn with Mg markedly enhances the role of oxygen in constituting electronic states around the Fermi level and its role in the electrochemical process leading to the improved capacity.

In this paper, the sorption of NH3, H2O, SO2 and CO2 was tested for several selected inorganic materials. The tests were performed on samples belonging to two topologies of materials, faujasite (FAU) and framework-type MFI, the structures of which differ in pore size and connectivity. All sorbates are important in terms of reducing their emissions to the environment. They have different chemical nature: basic, alkaline, and acidic. They are all polar in structure and composition and two of them (ammonia and water vapor) can form hydrogen bonds. These differences result in different interactions with the surface of the adsorbents. This paper presents experimental data and proposes a mathematical description of the sorption process. The best fit of the experimental data was obtained for the Toth and GAB models. The studies showed that among the selected samples, faujasite has the best sorption capacity for ammonia and water vapor, while the best sorbent for sulfur dioxide is the MFI framework type. These materials behave like molecular sieves and can be used for quite selective adsorption of relevant gases. In addition, modification of the faujasite with organic silane resulted in a drastic reduction in the surface area of the sorbent, resulting in significantly lower sorption capacities for gases.