Why have thermoelectric generator efficiencies remained relatively low despite research?

The relatively low efficiency of thermoelectric power generators is primarily due to the inherent physical limitations of the materials used to construct them. While research has advanced from early metallic conductors to semiconductor materials, achieving significant efficiency gains has proven difficult because of the complex interplay between thermal and electrical properties.1

To function effectively, these devices require materials that simultaneously possess high electrical conductivity and low thermal conductivity. However, these two properties are often linked in ways that hinder performance. Specifically, the operation of a generator involves:

• Thermal Conduction: Heat flows through the semiconductor legs, which is a necessary process but represents a loss of potential energy conversion.2
• Ohmic Heating: Electrical resistance within the material generates heat, which dissipates energy that would otherwise be converted into useful electrical power.2

Because these factors depend on the material's resistivity and thermal conductivity, the development of superior materials remains the critical barrier to exceeding current performance levels.12