Electrocaloric (EC) cooling represents a promising solid-state approach for next-generation thermal management. However, achieving substantial temperature modulation remains a challenge due to intrinsic material limitations and inefficient energy conversion. Herein, we focus on microstructure regulation to enhance thermal conductivity and EC performance. A hydroxyl-functionalized Ba<sub>0.63</sub>Sr<sub>0.37</sub>Zr<sub>0.01</sub>(Ti<sub>0.999</sub>