Beyond Inertness-A Critical Perspective on Design Strategies for Stable Thermoelectric Interfaces

Abstract

Interfacial stability in thermoelectric devices has evolved from empirical metallization toward a multi-objective engineering paradigm that integrates chemical, mechanical, and electronic considerations under prolonged high-temperature operation. This review critically analyses four dominant strategies: thermodynamic inertness, controlled reactivity, thermomechanical compliance, and kinetic suppression, highlighting their conceptual foundations, practical implementations, and inherent trade-offs. While achieving a sub-5 µΩ·cm² contact resistivity is now routine, the primary challenge lies in mitigating complex, multi-modal degradation pathways that dictate device lifetime. We argue for a strategic shift toward architected, functionally graded interfaces incorporating adhesion layers, electronic tuning, kinetic barriers, and mechanical buffers, supported by operando characterisation and predictive lifetime modelling. Furthermore, manufacturability and scalability of advanced designs must be rigorously assessed against industrial processes such as atmospheric plasma spraying and brazing. Mastering interfacial architectures is essential for enabling durable, commercially viable thermoelectric generators.