Self‐Reaction Effect‐Boosted Liquid Thermocell Based on Ethanol‐Aqueous Biphasic System

Abstract Low‐grade heat (<100 °C) energy sources possess considerable untapped potential for sustainable power generation. Liquid thermocells (LTCs) represent an innovative solution to convert low‐grade heat into electricity. The performance of LTCs relies on the combined effects of the Seebeck coefficient (S_e), electrical conductivity (σ_eff), and thermal conductivity (κ_eff). While previous studies have predominantly focused on enhancing S_e and σ_eff, κ_eff has received limited attention. Therefore, in this study, an electrochemically active biphasic liquid thermocell (EAB‐LTC) composed of ferrocene (Fc) and in an ethanol‐aqueous biphasic system is proposed. The self‐reaction of the redox couple enhances S_e, while the biphasic nature of the system suppresses thermal convection, resulting in reduced κ_eff. Compared to the conventional single‐phase LTC utilizing / , the S_e is increased by nearly threefold, accompanied by a more than threefold enhancement in output power. The application of the EAB‐LTC module is successfully demonstrated in powering electronic devices, thereby establishing a novel pathway for advancing high‐performance LTCs and presenting a promising approach toward achieving carbon neutrality.