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Solid-state thermoelectric technology,interconverting heat to electrical energy,offers a promising solution for relaxing global energy problems.A high dimensionless figure of merit ZT is desirable for high-efficiency thermoelectric power generation.Thus far,thermoelectric materials research has focused on increasing the material's ZT.Here we firstly fabricated phase-separated Sn1-xPbxSe materials by hydrothermal synthesis.We demonstrate that the simultaneous optimization of power factor and significant reduction in thermal conductivity can be achieved in phase-separated Sn1-xPbxSe material.The introduction of PbSe phase contributes to improvement on the electrical conductivity and power factor of the SnSe phase.Meanwhile,nanoscale precipitates and mesoscale grains define all-scale hierarchical architectures to scattering phonons,leading to low lattice thermal conductivity.These two favorable factors lead to achieve remarkably high thermoelectric performance ZT~1.7 at 873 K in polycrystalline SnSe+1%PbSe along the pressing direction,which is a record high ZT for SnSe polycrystals.These findings highlight the prospects of realizing highly effective solid-state thermoelectric devices.