# Electrically controlled heat transport in graphite films via reversible ionic liquid intercalation

## TL;DR

Researchers developed a way to control heat flow in graphite films using electric signals, which could lead to new thermal devices for aerospace and electronics.

## Contribution

A novel electrothermal switch using reversible ionic liquid intercalation in graphite films to modulate thermal conductivity.

## Key findings

- Graphite films' in-plane thermal conductivity was modulated over 13-fold via ion intercalation.
- The device enables electrically tunable heat flow with significant on/off ratios.

## Abstract

The ability to control heat transport with electrical signals has been an outstanding challenge due to the lack of efficient electrothermal materials. Previous attempts have mainly concentrated on low–thermal conductivity materials and encountered various problems such as narrow dynamic range and modest on/off ratios. Here, using high–thermal conductivity graphite films, we demonstrate an electrothermal switch enabling electrically tunable heat flow at the device level. The device uses reversible electro-intercalation of ions to modulate the in-plane thermal conductivity of graphite film by more than 13-fold via tunable phonon scattering, enabling observable modulation of the thermal conductivity at the device level. We anticipate that our results could provide a realistic pathway for adaptive thermal transport, enabling electrically driven thermal devices that would find a broad spectrum of applications in aerospace and microelectronics.

Reversible ion intercalation enables electrically tunable heat flow on graphite thin films.