Synthesis, structure, electrical properties and Na+ migration pathways of Na2CoP1.5As0.5O7

Synthesis, Electrical Properties and Na+ Migration Pathways of Na2CuP1.5As0.5O7

“…The valence unit was also recently related to potential energy scale and electrostatic interactions [19,20]. The BVSE method was used with success to simulate the transport pathways of monovalent cations (Na + ; K + and Ag + ) in numerous materials including Na 2 CoP 1.5 As 0.5 O 7 [15], Na 1.14 K 0.86 CoP 2 O 7 [25] and Ag 3.68 Co 2 (P 2 O 7 ) 2 [26]. The BVSE calculations were performed using the SoftBV [27] code and the visualization of isosurfaces was carried out using VESTA3 software (version 3, Koichi Momma and Fujio Izumi, 2018).…”

“…The Na 2 MP 2 O 7 systems (M = transition metal) [13,14] have a layered structure with the layers [MP 2 O 7 ] n 2n− and the sodium cations localized in the interlayer space, which favors high ionic conductivity. We recently investigated the effect of the substitution of P by As with a larger ionic radius for ionic conductivity and showed the improvement of ionic conductivity for Na 2 CoP 1.5 As 0.5 O 7 [15], which has an electrical conductivity value of σ 240 • C = 7.91×10 −5 Scm −1 and an activation energy Ea = 0.56 eV compared to Na 2 CoP 2 O 7 (σ 300 • C = 2 × 10 −5 Scm −1 ; Ea = 0.63 eV) [13].…”

Electrical properties and alkali-pathways simulation of new mixed conductor Na4Li0.62Co5.67Al0.71(AsO4)6

“…14 10 -4 Scm −1 at 160°C to 9.78 10 -4 Scm −1 at 445°C (table 3). Although, the absolute conductivity value of the Al/Li-substituted title material at 320°C (σ=2.64 10 -4 Scm −1 ) is greater than that of the parent material Na 4 Co 7 (AsO 4 ) 6 at 360 (2.51 10 -5 Scm −1 ) and of the Al-substituted Na 4 Co 5.63 Al 0.91 (AsO 4 ) 6 at 350°C (σ=6.6 10 -5 Scm −1 [19]), respectively.…”

“…Other arsenate materials belonging to the same structural type have been synthesized [18][19][20][21][22][23][24]. Especially, LiCoAsO 4 arsenate with olivine structure [25] shows interesting electrochemical properties.…”

“…The electrical measurements of cobalt arsenate compounds show interesting electrical performance such as Ag 4 Co 7 (AsO 4 ) 6 ; Na 4 Co 5.63 Al0 .91 (AsO 4 ) 6 and Na 4 Co 7 (AsO 4 ) 6 which are classified as fast electrical conductors [18][19][20].…”