Resolving Thermal Accumulation and Rigid–Soft Interface Mismatch in Stretchable Electronics with Cubic Boron Nitride Composite Islands

, respectively. Compared with the substrate without composite islands, the peak temperature is reduced by 12.8 °C. Furthermore, a stretchable computing platform based on this design maintains an operating temperature below 40 °C during practical operation, demonstrating an important thermal safety advantage for human-contact applications. In addition, the local modulus gradient created by the composite islands near the chip mitigates rigid-soft interfacial mismatch, thereby alleviating stress concentration and increasing stretchability from 70.41% to 122.67%. The proposed design further demonstrates long-term stability in soft robotic end-effectors and wearable systems, providing an effective strategy for achieving both thermal safety and mechanical reliability in highly integrated stretchable electronics.