The ability to actively regulate heat flow at the nanoscale could be a game changer for applications in thermal management and energy harvesting. Such a breakthrough could also enable the control of heat flow using thermal circuits, in a manner analogous to electronic circuits. Here we demonstrate switchable thermal transistors with an order of magnitude thermal on/off ratio, based on reversible electrochemical lithium intercalation in MoS2 thin films. We use spatially-resolved time-domain thermoreflectance to map the lithium ion distribution during device operation, and atomic force microscopy to show that the lithiated state correlates with increased thickness and surface roughness. First principles calculations reveal that the thermal conductance modulation is due to phonon scattering by lithium rattler modes, c-axis strain, and stacking disorder. This study lays the foundation for electrochemically-driven nanoscale thermal regulators, and establishes thermal metrology as a useful probe of spatio-temporal intercalant dynamics in nanomaterials.
@article{arxiv.1901.04639,
title = {An electrochemical thermal transistor},
author = {Aditya Sood and Feng Xiong and Shunda Chen and Haotian Wang and Daniele Selli and Jinsong Zhang and Connor J. McClellan and Jie Sun and Davide Donadio and Yi Cui and Eric Pop and Kenneth E. Goodson},
journal= {arXiv preprint arXiv:1901.04639},
year = {2019}
}