Isotope Engineering via Non-Equilibrium Unified Theory: A Dopant-Free Route to Advanced Energy Materials

Isotope engineering provides a pathway for tuning material properties without chemical

modification. In this work we apply the Non-Equilibrium Unified Theory (NEUT) to analyze

isotope-induced bond-length variations and their impact on functional materials.

The framework predicts picometer-scale bond-length shifts on the order of 0.01–0.03 ˚A.

Although small, such distortions can significantly affect phonon transport, electronic structure,

and ion diffusion.

Numerical estimates suggest that isotope engineering may reduce thermal conductivity by

approximately 20–24% in thermoelectric materials and improve the thermoelectric figure of merit

by up to 30%. The same framework predicts improvements in solid-state battery performance,

including increases in ionic conductivity and capacity retention.

These results suggest that isotope engineering offers a new dopant-free strategy for materials

optimization.