Thermomagnetic Generation Performance of Gd and La(Fe, Si)₁₃H_y/In Material for Low-Grade Waste Heat Recovery

The recovery of waste heat is urgently required to solve challenging energy and environmental issues. Thermomagnetic generation (TMG) technology using magnetic phase transition materials can realize the conversion of low-grade waste heat into electrical energy. However, efficient TMG materials hold the key to the development of this technology. Herein, the TMG performance of La(Fe, Si)₁₃H_y/In is studied in comparison with the benchmark material Gd systematically. The induced current I is related to the change rate of the average magnetization over time dM/dt according to Faraday's law. In addition, the location of T_C in the working temperature range is an important factor affecting TMG performance. Due to the sharper magnetic transition, La(Fe, Si)₁₃H_y/In presents a maximum intrinsic I of 9.12 µA g⁻¹, ≈90% higher than that of Gd (4.82 µA g⁻¹). Moreover, the average output electrical power density and cost performance of La(Fe, Si)₁₃H_y/In are 0.42 mW m⁻³ and 0.102 nW USD⁻¹, which are also significantly higher than those of Gd, 0.10 mW m⁻³ and 0.005 nW USD⁻¹, respectively. In comparison with Gd, the present work suggests that the La(Fe, Si)₁₃H_y/In possesses much higher potential in the field of low-grade waste heat recovery.