Effect of magnesium substitution on structural and dielectric properties of LiNiPO₄

Abstract

The aim of this paper is to study the effect of Mg 2+ doping in place of Ni in LiNiPO 4 compounds synthesized by solid state reaction method. As Mg is a relatively light and cheap, and is expected to stabilize the structure, it has been considered as a substituent for Ni. The structural and conductivity studies of the substituted phases are discussed in comparison with LiNiPO 4 . In this study, we have proposed cation-substituted compounds, LiNi 1 − x Mg x PO 4 (x = 0, 0.05, 0.1 and 0.15) where a part of the divalent state of Ni 2+ is replaced with the corresponding amount of Mg 2+ and where the charge compensation is maintained by lithium deficiency. It is possible to obtain the mentioned compounds because the pristine LiNiPO 4 compound is stable in ambient atmosphere, which differs considerably from the LiCoPO 4 compound.

Complex Dielectric and Impedance Spectroscopic Studies in a Multiferroic Composite of Bi2Fe4O9-BiFeO3

“…The ions that interact in its surrounding will introduce a perturbed potential and affect the motion of neighboring ions. Thus, this cooperative motion will give rise to a distribution of the relaxation time [25]. In general, the region to the left of the M"peak implies a range in which charge carriers are mobile over long distances, and that to the right is the range in which the carriers are confined to potential wells over a short range [13,26].…”

“…The ac conductivity (σac) study signifies the presence of single or multiple relaxation in the material. In this case, the ac conductivity plot with respect to frequency at different temperatures (cf Figure 10) can be divided into a low frequency plateau governed by random hopping of electrons contributing to dc conductivity and a high frequency dispersive region dependent upon ω n (where ω is the angular frequency and n is a constant dependent upon frequency and temperature) and defines the type of conductivity [28] related to the hopping of electrons between trap levels situated in the bandgap [25]. Conductivity plots are fitted well with Joanscher's power law, σ ac = σ dc + Aω n [29].…”

Investigation of Temperature- and Frequency- Dependent Dielectric Study of LiNi0.3Co0.3Mn0.3O2 and LiNi0.3Co0.3Mn0.3Ba0.1O2 for Cathode Materials

“…, the resistivity of the semiconducting material decreases with an increase in temperature, consequently resulting in an increase in its conductivity . In Z′ , all the peaks merged at higher frequencies because of the release of space charge on the surface of material . Broadening of peaks which were marginally asymmetrical in nature were observed in the graphs with an increase in the temperature, indicating the presence of a temperature-dependent relaxation phenomenon in the synthesized cathode materials.…”

“…21 In Z′, all the peaks merged at higher frequencies because of the release of space charge on the surface of material. 28 Broadening of peaks which were marginally asymmetrical in nature were observed in the graphs with an increase in the temperature, indicating the presence of a temperature-dependent relaxation phenomenon in the synthesized cathode materials. The multiple relaxation phenomena may be due to the grain, grain boundary, or interface effect.…”

The role of metal substitutions in the development of Li batteries, part I: cathodes

“…In practice, many synthesized LNP cathodes with coating and metal substitution break 100 mA h g À1 . Mg 2+ substitution has been shown to increase structural stability, 410 while Nd 3+ substitution was able to achieve a capacity of 95 mA h g À1 at 0.1C and retained 85% capacity after 50 cycles at 2C. 411 Recently, Co-substituted LNP nanosheets were able to be cycled for 200 cycles at 0.1C with 98% capacity retention and an initial reversible capacity of 133 mA h g À1 at that rate using an LNP/ Li 4 Ti 5 O 12 full cell with solid polymer electrolyte.…”