A thermo-electrochemical cell with a threaded graphite electrode towards low-grade heat recovery

Thermo-electrochemical cells (TECs) are a promising technology for converting low-grade thermal energy into electricity through redox reactions. Despite extensive research, TECs still face challenges in practical applications due to their complex assembly processes, susceptibility to leakage, limited electrode reaction area, and low efficiency. In this study, TECs featuring threaded graphite electrodes were constructed. Owing to the enhanced reaction area, high thermal conductivity, and excellent electrolyte sealing capability of the threaded graphite electrode configuration, the TECs demonstrate exceptional electrical output and long-term stability. Through systematic optimization of electrode materials, electrode spacing, and electrolyte composition, the Seebeck coefficient of the TECs reached 2.5 mV K^-1. Under a temperature difference of 20 K, the TECs achieved a maximum power output of 100 mW m^-2, representing a fourfold enhancement compared to the original cell. Furthermore, a TEC stack was developed based on optimized single-unit configurations. Comprehensive evaluation confirmed the stack's performance and operational stability, underscoring its significant potential for practical applications in low-grade thermal energy harvesting.