Anti‐Fatigue and Highly Conductive Thermocells for Continuous Electricity Generation

Abstract The integration of wearable technologies with the human body requires power supplies that are mechanically compatible and able to continuously generate electricity like biological systems. Distinct from existing batteries relying on periodic recharging, thermocells added with thermogalvanic ions are a promising candidate because they enable continuous electricity generation through redox reactions driven by ubiquitous waste heat. However, challenges remain in mechanical adaptability, fatigue resistance, and ion conduction, severely limiting thermocells’ sustainability and lifespan in practical applications. Herein, bionic mechanical training is applied to develop anti‐fatigue and highly conductive thermocells with hierarchical fibrils and aligned nanochannels. It achieves simultaneous enhancements in mechanical performance and output power density. Compared with existing quasi‐solid thermocells with disordered nano‐networks, there are ≈1790‐fold and 5‐fold increases in the mechanical toughness and ionic conductivity, respectively. The stretchability can accommodate the human body's deformation, and the power density is comparable to that of state‐of‐the‐art quasi‐solid thermocells. Moreover, this is the first demonstration of an anti‐fatigue thermocell with a threshold of 2500 J m −2 , which is comparable to that of natural muscles and enables it to take full advantage of the continuous energy conversion mode.