1：Experimental Design and Method Selection:

Polarization fatigue tests were conducted on bulk PMN-xPT single crystals and two types of 1-3 PMN-xPT/polymer composites with 'soft' and 'hard' epoxy fillers. The variations of remnant polarization, coercive electric field, and micro-crack morphology under 10 Hz cyclic electric loading were studied.

2：Sample Selection and Data Sources:

Rhombohedral phase

3：74Pb(Mg1/3Nb2/3)O3-26PbTiO3 (PMN-26PT) single crystals were used. Two different types of polymers were used as fillers:

'hard filler' epoxy (Epotek301) and 'soft filler' epoxy (Stycast 1365-55).

4：5). List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Precision Premier II (Radiant Technologies) for polarization fatigue characterization and P-E hysteresis loops measurement, TF Analyzer (2000e, ACCT, Inc.) for strain hysteresis measurement, and a polarizing light microscope (PLM) (Zessi Axiokop40) for domain observation.

5：Experimental Procedures and Operational Workflow:

The conventional dice and fill method was used to fabricate the 1-3 piezoelectric composites. After fabrication, the composites were poled along [001]c, and then subjected to cyclic electric loading.

6：Data Analysis Methods:

The coercive field and remnant polarization were analyzed to evaluate the fatigue behavior. Micro-crack morphology was observed to understand the fatigue mechanism.