Thermo-transport properties of Zn-substituted layered Li-nickel oxide, $$\hbox {LiNiO}_{2}$$ LiNiO 2

Abstract

The layered Li-TM-O 2 materials have been investigated extensively due to their application as cathodes in Li batteries. The electrical properties of these oxides can be tuned or controlled either by non-stoichiometry or substitution. Hence the thermo-transport properties of Zn-substituted LiNi 1−x Zn x O 2 for 0 ≤ x ≤ 0.16 have been investigated in the temperature range of 300-900 K for potential application as a high-temperature thermoelectric material. For x < 0.08, the compounds were of single phase belonging to the space group R-3mH while for x > 0.08 an additional minority phase, ZnO forms together with the main layered phase. All the compounds exhibit a semiconducting behaviour with electrical resistivity, varying in the range of ∼10 −4 to 10 −2 m between 300 and 900 K. The electrical resistivity is found to increase with increasing Zn-substitution predominantly due to a decrease in the charge carrier hole mobility. The activation energy remains constant, ∼10 meV, with Zn-substitution. The Seebeck coefficient of the compounds is found to decrease with increasing temperature and increase with increasing Zn-substitution. The Seebeck coefficient decreases from ∼95 to 35 μV K −1 and the corresponding power factor is ∼12 μW m −1 K −2 for the x = 0.16 compound.