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Segmented thermoelectric generators (TEGs) comprising multiple TE elements can operate over a large thermal gradient without inherent conversion efficiency (ZT) losses of materials. However, despite excellent theoretical efficiencies, the performance of actual segmented TEGs are critically affected by several challenges related to material incompatibility and limited design flexibility in conventional fabrication processes. Herein, we report the multi-material 3D printing of composition-segmented BiSbTe materials by the sequential deposition of all-inorganic viscoelastic TE inks containing BixSb2-xTe3particles, tailored with Sb2Te42−chalcogenidometallate binders. The peak ZTs of the 3D-printed materials controllably shifted from room temperature to 250 °C by composition engineering of BixSb2-xTe3particles. We fabricated the optimally designed TEG comprising the 3D-printed, composition-segmented tri-block Bi0.55Sb1.45Te3/Bi0.5Sb1.5Te3/Bi0.35Sb1.65Te3TE leg, which extends the peak ZTs and satisfies full compatibility across the entire temperature range, realizing a record-high efficiency of 8.7% under the temperature difference of 236 °C. Our approach offers a promising strategy to optimize segmented TEGs.