Crystal growth of mixed‐valence ammonium vanadates

Abstract

A new method has been developed for the synthesis of mixed-valence ammonium vanadate crystals. Single crystals of (NH 4 ) 2 V 3 O 8 were synthesized on a large scale by hydrothermal reduction of NH 4 VO 3 in ethanol-H 2 O solutions in the presence of triblock copolymer Pluronic P123. The crystals are shining thin plates with (001) cleavage planes. Calcination of the (NH 4 ) 2 V 3 O 8 crystals at 300°C or above resulted in pure phases of V 2 O 5 .

Facile synthesis and lithium storage performance of (NH4)2V3O8 nanoflakes

“…Figure 1b illustrates the crystal structure of (NH 4 ) 2 V 3 O 8 . It is clearly seen that (NH 4 ) 2 V 3 O 8 has a lamellar structure that consists of layers of corner-sharing VO 4 tetrahedra and VO 5 square pyramids [14]. Similar to NH 4 V 3 O 8 , the NH 4 ?…”

“…and V 5? , respectively [14]. The relatively weak band at 935.06 cm -1 is assigned to V-OÁÁÁH vibrations or the hydrogen bonds (N-HÁÁÁO) between NH 4 ?…”

Structural hierarchy of NH4V3O7 particles prepared under hydrothermal conditions

“…Particularly, to date, a few compounds in the family of ammonium polyvanadates are known -NH 4 V 4 O 10 [9][10][11][12], NH 4 V 4 O 14 [13], (NH 4 ) 2 V 3 O 8 [14], NH 4 V 3 O 7 [15]. Large NH + 4 -ions stabilize the internal pillarlike cavities within the vanadate frameworks, leading to enhanced diffusion rate of lithium ions.…”

Simple Preparation of V2O5Nanostructures and Their Characterization

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Layerstructured vanadium pentoxide is one of the most studied vanadium oxides despite its low discharge voltages, low electric conductivity, and slow diffusion kinetics of lithium ions. [6][7][8][9][10][11][12][13] In order to improve the performance of lithium batteries by employing vanadium pentoxide as a cathode material, a few methods have been used to prepare vanadium pentoxide with better characteristics, which includes the use of aerogels, xerogels, nanocomposites of LiV 2 O 5 with electronically conducting organic polymers and nanostructured materials.…”

“…Generally, nanomaterials are prepared in acidic media [2][3][4][5] but very few studies report their synthesis using basic media. 17 Here, we report synthesis of nanosized vanadium oxides by thermal decomposition of ammonium vanadate nanomaterials prepared via refluxing and precipitation methods in both basic and acidic media.…”