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Sodium-based layered oxides undergo several structural changes upon the (de-)sodiation process and reveal a strong tendency towards water intercalation at lower sodium contents. However, valuable information about their handling during the investigation are still rare. Herein, we report an investigation of the water sensitivity of layered NaxNi0.22Co0.11Mn0.66O2 with mixed P2/P3 structure via X-ray diffraction. At lower sodium contents, i.e. below x ≈ 0.33 or above 3.6 V vs. Na/Na+, a strong tendency for the uptake of water is observed, supported by the appearance of new diffraction peaks confirming a dramatically increased interlayer distance. However, at high sodium content (x > 0.33) the material can be processed in open air without major changes. [ABSTRACT FROM AUTHOR]

Abstract: Sodium-ion batteries (SIBs) are considered to be a promising low-cost alternative to common lithium-ion batteries. Herein, we present a detailed electrochemical characterization of anatase TiO2 nanoparticles as anode material for Na-ion batteries, highlighting the substantial influence of the electrolyte composition (salt and solvent) on the obtainable specific capacity, cycling stability, and particularly the coulombic efficiency. TiO2-based electrodes cycled using a 1M solution of NaClO4 in a mixture of ethylene carbonate and propylene carbonate present excellent high rate capability, offering about 100 and 86 mAh g−1 at 5.5 and 11C, respectively, which is – to the best of our knowledge – the best high rate capability for all titanium-based sodium-ion anode materials reported so far. Setting the C rate to 5.5C (i.e., 1.85 A g−1), such electrodes can be cycled for more than 1000 cycles without significant capacity decay, confirming their outstanding durability at such high specific current. These results, in combination with its environmental friendliness and cost efficiency, render anatase TiO2 nanoparticles a promising anode material for high power sodium-ion batteries. [Copyright &y& Elsevier]