High-efficiency electrochemical thermal energy harvester using carbon nanotube aerogel sheet electrodes

TLDR

Low‑grade waste heat conversion to electricity is a key energy harvesting strategy, yet efficient, inexpensive devices are scarce. The study aims to fabricate low‑cost, high‑efficiency carbon nanotube aerogel thermo‑electrochemical cells. The authors constructed thermo‑electrochemical cells using carbon nanotube aerogel sheet electrodes. The cells delivered a peak power density of 6.6 W m⁻² at a 51 °C temperature difference, corresponding to 3.95 % Carnot‑relative efficiency, and demonstrated that electrode purity, engineered porosity, and catalytic surfaces enhance performance.

Abstract

Abstract Conversion of low-grade waste heat into electricity is an important energy harvesting strategy. However, abundant heat from these low-grade thermal streams cannot be harvested readily because of the absence of efficient, inexpensive devices that can convert the waste heat into electricity. Here we fabricate carbon nanotube aerogel-based thermo-electrochemical cells, which are potentially low-cost and relatively high-efficiency materials for this application. When normalized to the cell cross-sectional area, a maximum power output of 6.6 W m −2 is obtained for a 51 °C inter-electrode temperature difference, with a Carnot-relative efficiency of 3.95%. The importance of electrode purity, engineered porosity and catalytic surfaces in enhancing the thermocell performance is demonstrated.