High Power Density Thermoelectric Generators with Skutterudites

Abstract Thermoelectric generators (TEGs) offer a versatile solution to convert low‐grade heat into useful electrical power. While reducing the length of the active thermoelectric legs provides an efficient strategy to increase the maximum output power density p_max, both the high electrical contact resistances and thermomechanical stresses are two central issues that have so far prevented a strong reduction in the volume of thermoelectric materials integrated. Here, it is demonstrated that these barriers can be lifted by using a nonconventional architecture of the legs which involves inserting thick metallic layers. Using skutterudites as a proof‐of‐principle, several single‐couple and multi‐couple TEGs with skutterudite layers of only 1 mm are fabricated, yielding record p_max ranging from 3.4 up to 7.6 W cm⁻² under temperature differences varying between 450 and 630 K. The highest p_max achieved corresponds to a 60‐fold increase per unit volume of skutterudites compared to 1 cm long legs. This work establishes thick metallic layers as a robust strategy through which high power density TEGs may be developed.