Breaking through the Optimization Limits of Power Factor via Pressure-Decoupled Seebeck Coefficient and Electrical Conductivity

In thermoelectricity, the inherent coupling between electrical conductivity and Seebeck coefficient represents a fundamental challenge in thermoelectric materials development. Herein, we present a unique pressure-tuning strategy using compressible layered 2H-MoTe₂, achieving an effective decoupling between the electrical conductivity and Seebeck coefficient. The applied pressure simultaneously induces two complementary effects: (1) bandgap reduction that moderately enhances carrier concentration to improve the electrical conductivity, and (2) band convergence that dramatically increases density-of-states effective mass to boost the Seebeck coefficient. This dual mechanism yields an extraordinary 18.5-fold enhancement in the average power factor. Firstprinciples calculations and Boltzmann transport modeling precisely reproduce the experimental observations, validating this pressure-induced decoupling mechanism. The pressure-tuning mechanism provides a feasible and effective strategy for breaking through the optimization limits of power factor, facilitating to design high-performance thermoelectric materials.