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

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 over thirteen-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 a new class of electrically driven thermal devices which would find a broad spectrum of applications in aerospace and microelectronics.