| Summary: | Ferroelectric property that induces electrocaloric effect was investigated in Ba(Ge<i><sub>x</sub></i>Ti<sub>1−<i>x</i></sub>)O<sub>3</sub> ceramics, known as BTGx. X-ray diffraction analysis shows pure perovskite phases in tetragonal symmetry compatible with the <i>P</i>4<i>mm</i> (No. 99) space group. Dielectric permittivity exhibits first-order ferroelectric-paraelectric phase transition, confirmed by specific heat measurements, similar to that observed in BaTiO<sub>3</sub> (BTO) crystal. Curie temperature varies weakly as a function of Ge-content. Using the direct and indirect method, we confirmed that the adiabatic temperature change Δ<i>T</i> reached its higher value of 0.9 K under 8 kV/cm for the composition BTG6, corresponding to an electrocaloric responsivity Δ<i>T</i><i>/</i>Δ<i>E</i> of 1.13 × 10<sup>−6</sup> K.m/V. Such electrocaloric responsivity significantly exceeds those obtained so far in other barium titanate-based lead-free electrocaloric ceramic materials. Energy storage investigations show promising results: stored energy density of ~17 mJ/cm<sup>3</sup> and an energy efficiency of ~88% in the composition BTG5. These results classify the studied materials as candidates for cooling devices and energy storage applications.
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