Limits...
Experimental visualization of the diffusion pathway of sodium ions in the Na 3 [Ti 2 P 2 O 10 F] anode for sodium-ion battery

View Article: PubMed Central - PubMed

ABSTRACT

Sodium-ion batteries have attracted considerable interest as an alternative to lithium-ion batteries for electric storage applications because of the low cost and natural abundance of sodium resources. The materials with an open framework are highly desired for Na-ion insertion/extraction. Here we report on the first visualization of the sodium-ion diffusion path in Na3[Ti2P2O10F] through high-temperature neutron powder diffraction experiments. The evolution of the Na-ion displacements of Na3[Ti2P2O10F] was investigated with high-temperature neutron diffraction (HTND) from room temperature to 600°C; difference Fourier maps were utilized to estimate the Na nuclear-density distribution. Temperature-driven Na displacements indicates that sodium-ion diffusion paths are established within the ab plane. As an anode for sodium-ion batteries, Na3[Ti2P2O10F] exhibits a reversible capacity of ~100 mAh g−1 with lower intercalation voltage. It also shows good cycling stability and rate capability, making it promising applications in sodium-ion batteries.

No MeSH data available.


Related in: MedlinePlus

Crystal structure of tetragonal Na3[Ti2P2O10F] observed (a) approximately along the a axis and (b) along the c axis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5384114&req=5

f2: Crystal structure of tetragonal Na3[Ti2P2O10F] observed (a) approximately along the a axis and (b) along the c axis.

Mentions: Figure 2 shows a schematic view of the crystal structure of Na3[Ti2P2O10F]. The structure consists of layers of TiO5F octahedra and PO4 tetrahedra sharing corners; Na atoms are interleaved between the layers. TiO5F octahedra contain four Ti–O1 equatorial distances of 2.0108(1) Å, a very short Ti–O2 axial bond length of 1.699(4) Å which can be considered as a titanyl Ti–O terminal double bond in the framework33 and an opposite Ti–F bond of 2.111(3) Å. Within the tetrahedron P–O1 distances take values of 1.5323(9) Å, adopting an ideal tetrahedral geometry. Na atoms present a sevenfold coordination environment with four Na–O1 bond-lengths (2.501(2) Å), two Na–O2 bonds (2.539(3) Å) and a weak bond to F (2.505(3) Å); as a reference in NaF, the Na–F distance is 2.316 Å. Figure 2b shows a projection of the structure along the c axis, which can be described as a repeat stacking of a buckled square-net sheet. As mentioned above, the Ti–O2 double bond contains a terminal oxygen that does not contribute to the connection between the sheets. The square-net sheets are interconnected thereby only through sharing F atoms on TiFO5 octahedra. Because of the long Ti–F–Ti distance (~4.3 Å), the framework structure is quite open, containing two-dimensional (2D) channels where Na atoms are located.


Experimental visualization of the diffusion pathway of sodium ions in the Na 3 [Ti 2 P 2 O 10 F] anode for sodium-ion battery
Crystal structure of tetragonal Na3[Ti2P2O10F] observed (a) approximately along the a axis and (b) along the c axis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384114&req=5

f2: Crystal structure of tetragonal Na3[Ti2P2O10F] observed (a) approximately along the a axis and (b) along the c axis.
Mentions: Figure 2 shows a schematic view of the crystal structure of Na3[Ti2P2O10F]. The structure consists of layers of TiO5F octahedra and PO4 tetrahedra sharing corners; Na atoms are interleaved between the layers. TiO5F octahedra contain four Ti–O1 equatorial distances of 2.0108(1) Å, a very short Ti–O2 axial bond length of 1.699(4) Å which can be considered as a titanyl Ti–O terminal double bond in the framework33 and an opposite Ti–F bond of 2.111(3) Å. Within the tetrahedron P–O1 distances take values of 1.5323(9) Å, adopting an ideal tetrahedral geometry. Na atoms present a sevenfold coordination environment with four Na–O1 bond-lengths (2.501(2) Å), two Na–O2 bonds (2.539(3) Å) and a weak bond to F (2.505(3) Å); as a reference in NaF, the Na–F distance is 2.316 Å. Figure 2b shows a projection of the structure along the c axis, which can be described as a repeat stacking of a buckled square-net sheet. As mentioned above, the Ti–O2 double bond contains a terminal oxygen that does not contribute to the connection between the sheets. The square-net sheets are interconnected thereby only through sharing F atoms on TiFO5 octahedra. Because of the long Ti–F–Ti distance (~4.3 Å), the framework structure is quite open, containing two-dimensional (2D) channels where Na atoms are located.

View Article: PubMed Central - PubMed

ABSTRACT

Sodium-ion batteries have attracted considerable interest as an alternative to lithium-ion batteries for electric storage applications because of the low cost and natural abundance of sodium resources. The materials with an open framework are highly desired for Na-ion insertion/extraction. Here we report on the first visualization of the sodium-ion diffusion path in Na3[Ti2P2O10F] through high-temperature neutron powder diffraction experiments. The evolution of the Na-ion displacements of Na3[Ti2P2O10F] was investigated with high-temperature neutron diffraction (HTND) from room temperature to 600°C; difference Fourier maps were utilized to estimate the Na nuclear-density distribution. Temperature-driven Na displacements indicates that sodium-ion diffusion paths are established within the ab plane. As an anode for sodium-ion batteries, Na3[Ti2P2O10F] exhibits a reversible capacity of ~100 mAh g−1 with lower intercalation voltage. It also shows good cycling stability and rate capability, making it promising applications in sodium-ion batteries.

No MeSH data available.


Related in: MedlinePlus