Thermoelectric properties of Cu2Se/xNi0.85Se hot-pressed from hydrothermal synthesis nanopowders

The [Formula: see text] ([Formula: see text] = 0, 0.025, 0.05, 0.075, 0.1, 0.15, 0.2, 0.3, 0.4 and 0.5) nanopowders were synthesized by the hydrothermal method and then were hot-pressed into bulk alloys. The effects of [Formula: see text] secondary phase on the thermoelectric (TE) properties of [Formula: see text] were investigated. For [Formula: see text] and [Formula: see text], both their electrical resistivity and Seebeck coefficients increase. While for [Formula: see text], they decrease instead. The samples for [Formula: see text] have lower thermal conductivity. However, for [Formula: see text], the thermal conductivity rises remarkably. As an overall result, the maximum value of dimensionless TE figure of merit (ZT) reaches 1.52 at 873 K for the sample of [Formula: see text], 36.5% higher than for the sample without [Formula: see text].