Cheap, Large-Scale, and High-Performance Graphite-Based Flexible Thermoelectric Materials and Devices with Supernormal Industry Feasibility

Flexible thermoelectric materials and devices show great potential to solve the energy crisis but still face great challenges of high cost, complex fabrication, and tedious postprocessing. Searching for abnormal thermoelectric materials with rapid and scale-up production can significantly accelerate their applications. Here, we develop superlarge 25 x 20 cm(2) commercial graphite-produced composite films in batches, achieved by a standard 10 min industrial process. The high cost effectiveness (S-2 sigma/cost) of 7250 mu W g m(-1) K-2 $(-1) is absolutely ahead of that of the existing thermoelectric materials. The optimized composite film shows a high power factor of 94 mu W m(-1) K-2 at 150 degrees C, representing the optimal value of normal carbon materials so far. Furthermore, we design two types of flexible thermoelectric devices fabricated based on such a novel composite, which achieve an output open-circuit voltage of 3.70 mV using the human wrist as the heat source and 1.33 mV soaking in river water as the cold source. Our study provides distinguished inspiration to enrich flexible and cost-effective thermoelectric materials with industrial production.

Automated summary

This study successfully developed superlarge commercial graphite-produced composite films and achieved rapid production through standard industrial processes. The optimized composite film showed a high power factor at high temperatures, making it more cost-effective than existing thermoelectric materials. Additionally, two types of flexible thermoelectric devices were designed based on this composite material, demonstrating high voltage output.