Bistable origami thermal switch with high switching ratios

Effective thermal management is critical for power electronics in AI and robotics, highlighting the need for dynamic, reversible thermal switches. Achieving a high switching ratio remains challenging. Here, we present a bistable origami-inspired thermal switch that switch rapidly between distinct thermal conduction states without external energy or sensory input. Fabricated from a thin film through precise cut-and-fold, it achieves thermal switching ratios of 13,984 in vacuum and 1360 in ambient air, significantly higher than existing approaches. Switching is driven by snap-through instability, actuated by a combination of shape-memory alloy and elastic springs. The energy landscape can be tuned through geometric variations to adjust triggering temperature and switching ratio. We demonstrate stable, repeatable thermal regulation across multiple scenarios, offering a pathway toward passive, programmable thermal management.