1 research outputs found
Effects of the Particle Size Distribution and of the Electrolyte Salt on the Intercalation Properties of <i>P</i>3‑Na<sub>2/3</sub>Ni<sub>1/2</sub>Mn<sub>1/2</sub>O<sub>2</sub>
No full textSodium-deficient
nickel–manganese oxides with a layered
type of structure are, nowadays, of great interest as electrode materials
for both lithium- and sodium-ion batteries since they are able to
intercalate lithium and sodium ions reversibly within a broad concentration
range. Herein, we report new data on the effects of the particle sizes
and of the electrolyte salt on the intercalation properties of Na<sub>2/3</sub>Ni<sub>0.5</sub>Mn<sub>0.5</sub>O<sub>2</sub> with a <i>P</i>3-type of structure. The morphology of layered Na<sub>2/3</sub>Ni<sub>0.5</sub>Mn<sub>0.5</sub>O<sub>2</sub> oxides has been varied
by changing the type of the precursor used: from Na–Ni–Mn
acetates to Na–Ni–Mn mixed nitrate acetates. The structure,
particle dimensions, and particle size distribution of oxides have
been determined by means of powder X-ray diffraction (XRD), transmission
electron microscopy (TEM), dynamic light-scattering measurements,
and X-ray photoelectron spectroscopy (XPS). The intercalation properties
of Na<sub>2/3</sub>Ni<sub>0.5</sub>Mn<sub>0.5</sub>O<sub>2</sub> have
been studied in model electrochemical cells versus Li metal as the
anode. We used two kinds of lithium salts dissolved in organic solutions
as the electrolytes: 1 M LiPF<sub>6</sub> in EC:DMC and 1 M LiBF<sub>4</sub> in EC:DMC. The mechanism of the lithium intercalation into
Na<sub>2/3</sub>Ni<sub>0.5</sub>Mn<sub>0.5</sub>O<sub>2</sub> is discussed
on the basis of <i>e</i><i>x situ</i> XRD, HRTEM,
and X-ray photoelectron spectroscopy analyses. It has been discovered
that the lithium salt in the electrolyte salt contributes to the mechanism
of the electrochemical reaction, while particle dimensions determine
the capacity stability during continuous cycling, as well as the surface
reactivity of oxide electrodes
