where tPD, tNP, tp–p and tIF are the relaxation times corresponding to scattering from the point defect, nanoinclusions,phonon–phonon interactions and interfaces, respectively.Obviously, the reduction of kL in the composite samples 1#,2# and 3# should be attributed to the additional phononscattering from nanoinclusion (tNP) and the formed phaseboundaries (tIF). However, we notice that with f increasingfrom 1 to 2 and 3 vol%, kL rises instead of continuous falling,which could be caused by the inherent large lattice thermalconductivity kL of Cu3SbSe4,27 which means that large proportion of its existence will inevitably lead to the increase in theoverall kL of the composite system.