Enhancing P-type and N-type thermocells performance with carboxylated chitosan additive

Low-grade heat (<100 °C) is abundant and ubiquitous in the environment, and the recovery of low-grade heat energy will be of great significance for the energy supply and the improvement of the environment. Low-cost and effective technologies for transforming low-grade heat into electricity are urgently needed. Thermocell (TEC) based on REDOX couples has become a promising technology for low-grade heat harvesting due to its advantages of low cost, scalability, and intrinsic high thermopower. To enhance its performance, different types of TECs need to incorporate various additives into the REDOX couples. However, there is currently no identical additive that effectively enhances the performance of both P-type and N-type TECs. In this paper, carboxylated chitosan is used as an identical additive, resulting in an increase in the Seebeck coefficient of P-type and N-type TECs by 115.33 % and 53.25 %, respectively. Furthermore, we introduce a novel sandwich-structured packing technique featuring a configuration of Metal/PET film/Carbon felt (MPC) for TEC. This approach effectively reduces both the cost and weight of the TEC, while the MPC structure further enhances their performance. The TEC can be scaled up to power electrical devices. Our achievement provides an effective strategy for harvesting low-grade heat energy.