Physical properties of new ordered bimetallic phases M_0.25Cd_0.75PS₃ (M = Zn^II, Ni^II, Co^II, Mn^II)

Abstract

The characterization of four new ordered bimetallic phases together with the analysis of their magnetic, conducting and optical properties.

First-principles LCAO study of the low and room temperature phases of CdPS$_3$

“…2). Its value E g =3.4 eV for the C2/m phase is close to the experimental ones, ranging from 2.95 to 3.5 eV [11,12,13,14,15]. The experimental data for the band gap in the R3 phase are not available to our knowledge, and our calculations predict a value of 3.3 eV.…”

“…The atoms occupy the following Wyckoff positions: Cd 4g(0,y,0), P 4i(x,0,z), S1 4i(x,0,z), S2 8j(x,y,z) (Table 1). The experimental band gap E g is equal to 2.95 eV [11],…”

Lithium Storage Performance Boosted via Delocalizing Charge in ZnxCo1−xPS3/CoS2 of 2D/3D Heterostructure

“…[ 30 ] A closer look at the main (001) peak in the angle range of 13.3–14.8° reveals a gradual shift from the peak position of CoPS 3 to that of ZnPS 3 at the low angle with increasing ratio of Zn 2+ ions. Considering that the ionic radii of Zn 2+ (0.74 Å) and Co 2+ (0.72 Å) are quite comparative in a six coordination sphere, [ 17 ] this peak‐shift phenomenon could be caused by the expansion of lattice constant when the Co 2+ ions are partially substituted by Zn 2+ ions with a larger radius. Taking the XRD pattern of Zn 0.5 Co 0.5 PS 3 /CoS 2 (ZCPS/CS) composite with Zn: Co of 5:5 as an example, the calculated spacing of (001) planes in Zn 0.5 Co 0.5 PS 3 (ZCPS) is 6.397 Å, suggesting an overall increase by ≈0.153 Å with respect to pure CoPS 3 (6.243 Å).…”

“…For instance, it only needs a low activation energy for Zn 2+ in ZnPS 3 to diffuse within the layer via vacancy hopping. [ 17 ] Moreover, MPS 3 compounds with an internal electric field caused by its intrinsically asymmetric‐layered structure can locally accelerate the ion or electron migrations and the electrochemical reaction dynamic. [ 18 ] The intercalation with alkali cation K + can create a high concentration of cation vacancies in MnPS 3 lattice and increase its conductivity 10 6 ‐fold.…”

“…It has been proved that Zn‐doped can significantly improve the electric conductivity of CdPS 3 to 9.3 × 10 −10 S cm −1 , which is higher than that of other bimetallic (CoCd, MnCd, and NiCd) thiophosphates due to the moderate difference of electronegativity between Zn (1.65) and Cd (1.69). [ 17 ] Moreover, NiPS 3 /CoPS 3 heterostructure can exert less stress than its monometal counterpart during the lithiation process, effectively avoiding the structure from destroying. Hence, in order to achieve high electrochemical activity of MPS 3 and stabilize the structure upon lithiation, there is a need to tailor the geometry of MPS 3 .…”