The crystal structures and quasi-one-dimensional electronic properties of Ag_1+xV₃O₈and Na_1+xV₃O₈

Abstract

The crystal structures of M 1+x V 3 O 8 , where M 1+x = Ag 1.229 and Na 1.164 , isomorphous to the Li 1+x V 3 O 8 insertion electrode have been determined with x-ray four-circle diffraction. The networks of V ions are similar to each other, but significant differences for the M-O and M-M distances exist. The present results indicate that the Li insertion for the Ag system forces the Ag-O distance to be short, which results in an irreversible charge-discharge process accompanied with a deposition reduction of Ag ions. Both the Ag and the Na system exhibit that the donated electrons reside at specific V sites, which leads to quasi-one-dimensional electronic properties along the monoclinic baxis notwithstanding the complicated structure. The semiconducting transport mechanism is of variable-range hopping in one dimension and the magnetic properties are explained with a one-dimensional Heisenberg-like model.

Mo-doped LiV3O8 nanorod-assembled nanosheets as a high performance cathode material for lithium ion batteries

“…11 The theoretical capacity of LiV 3 O 8 with 3 Li intercalations/deintercalations is about 280 mA h g À1 , which is much higher than those of the currently used cathode materials, [12][13][14] making it a highly potential cathode material for next-generation LIBs. However, LiV 3 O 8 as a cathode material has relatively low electronic conductivity (approximately 10 À6 S cm À1 ) 15,16 and a low Li-ion diffusion coefficient (i.e., $10 À13 cm 2 s À1 ), 17 both of which signicantly limit its electrochemical property and practical applications as a cathode in LIBs. Numerous strategies have been investigated with the aim of improving the electrical conductivity and diffusion coefficient of LiV 3 O 8 , including the synthesis of different structured materials, metal ion doping, carbon or other conductive material coating, and reducing the particle size to nanometers.…”

Symmetric Aqueous Rechargeable Lithium Battery Using Na1.16V3O8Nanobelts Electrodes for Safe High Volume Energy Storage Applications

“…As such, solid state synthesis of Na 1.16 V 3 O 8 using V 2 O 5 and Na 2 CO 3 has been previously reported by M.Onoda 37 while the effect on crystallinity of Na 1+x V 3 O 8 during the electrochemical lithium insertion / deinsertion processes has been studied by Kawakita et al 35 Wang et al 38 has studied the use of Na 2 V 6 O 16 nanowire for LIBs, which gave a initial specific discharge capacity of 268 mAh g −1 and improved cycling stability upon heat-treatment of the compound. According Wang et.al, Na 2 V 6 O 16 .xH 2 O shows a different crystal structure from NaV 3 O 8 , thereby different electrochemical performance.…”

“…51 Therefore, electronic and ionic wirings of the active mass which allows faster pathways to conduct ions and electrons are crucial for high-rate capabilities. The layered crystal structure of Na 1.16 V 3 O 8 facilitates the lithium insertion / de-insertion into and from the layers via the diffusion, while presence of sodium ions (Na + ) residing in the octahedral sites [37][38][39] aids in maintaining the layered structure, by supporting the V 3 O 8 − puckered layers, during the electrochemical lithiation / de-lithiation processes, resulting in excellent electrochemical performance in terms of rate capability and cyclic stability. 28,39 The superior electrochemical performance of NVO-400, among NVO-200 and NVO-300, can be attributed to the larger cell volume and crystal size.…”

Spatiotemporal Resolution of Phase Formation in Thick Porous Sodium Vanadium Oxide (NaV3O8) Electrodes via Operando Energy Dispersive X-ray Diffraction

“…X-ray diffraction was used to characterize the cathode samples after discharge at high and low rates, indexing to the parent NVO (NaV 3 O 8 , Figure 1 a), 20 monohydrated NaV 3 O 8 ·H 2 O ( Figure 1 b), 21 and the reduction products ZHS (Zn 4 (SO 4 )(OH) 6 ·5H 2 O, Figure 1 c, [PDF# 00–039–0688]) 32 and ZVO (Zn 3 (OH) 2 V 2 O 7 ·2H 2 O, Figure 1 d, [PDF# 00–050–0570]). 33 The crystallographic parameters for these phases are provided in the Supporting Information Table S3 .…”

“… 9 − 16 Initial reports reveal that the NVO electrochemistry are strongly influenced by the material properties, especially structural hydration 13 , 14 , 17 and morphology. 10 , 18 , 19 Specifically for the sodium vanadium oxide (NaV 3 O 8 , NVO, Figure 1 a) 20 and its monohydrated form (NaV 3 O 8 ·H 2 O ( Figure 1 b)), 21 two additional phases have been previously identified to form as a result of electrochemical reduction in an aqueous zinc battery. 18 , 19 One of these phases is zinc hydroxy-sulfate (Zn 4 (SO 4 )(OH) 6 ·5H 2 O (ZHS) [PDF# 00–039–0688], Figure 1 c), which has been previously detected on the surface of the NVO cathode and has been attributed to H + insertion in NVO during discharge 14 , 22 , 23 where the H + insertion is accompanied by local pH change and precipitation of the ZHS.…”