Comparative study of Na3V2Ox(PO4)2F3-x prepared via solid-state and hydrothermal synthesis

Effect of the Particles Morphology on the Electrochemical Performance of Na3V2(PO4)2F3‐yOy

“…It appears thus that a partial oxidation of the V 3+ precursor takes place in the conditions used during the solvothermal syntheses due to presence of oxidative solvent. It clearly shows the difficulty to control the oxygen content (vanadium oxidation state) by using solvothermal approach [45] …”

Particle nanosizing and coating with an ionic liquid: two routes to improve the transport properties of Na3V2(PO4)2FO2

“…34,35 However, this synthesis process leads most often to partial oxidation of vanadium and to a V 3+ /V 4+ ratio difficult to be controlled in the final composition, which drastically affects the energy storage performance and thus makes it difficult to evaluate the sole influence of morphology. 34,36–39 Recently, Olchowka et al have reported an original ionothermal synthesis method leading to NVPFO 2 particles coated with an EMI TFSI ionic liquid (IL). 40 Their energy storage performance appears promising, even if the effect of IL coating is not fully understood yet.…”

A comprehensive review on recent advances of polyanionic cathode materials in Na‐ion batteries for cost effective energy storage applications

“…When the cycling rate increases to 2 C, the specific discharge capacity changes from 113 to 97 mAh/g, and from 102 to 34 mAh/g for the samples prepared by solid-state and hydrothermal routes, respectively. The better performance of the sample prepared by solid state route could be attributed to the increased surface area, which provides better contact of the cathode particles with the electrolyte and accelerates the diffusion processes through SEI (Semykina et al, 2020). However, Na 3 V 2 (PO 4 ) 2 F 3 is shown to co-exist with the Na 3 V 2 (PO 4 ) 3 phase at the high annealing temperature due to the fluorine loss and is accompanied by the formation of V 2 O 3 , Na 3 V 2 (PO 4 ) 3 , and Na 3 VF 6 .…”

“…Also, about 10 nm thin conducting carbon coating was obtained through the surface polymerization of the dopamine, which shows the improved rate capability and capacity retention (Burova et al, 2019). A comparative study is laid by the synthesis of Na 3 V 2 O x (PO 4 ) 2 F 3− x by solid‐state and hydrothermal methods (Semykina et al, 2020). The voltage plateaus appear at about 3.8 V/4.3 V in samples prepared by solid‐state and the reversible capacity of 113 mAh/g; while for the hydrothermally prepared sample, a specific capacity of 102 mAh/g is observed at C/10 rate.…”