Fig. 3.

Thermal transistor characteristics. a Optical micrograph of the device showing the location of real-time TDTR measurements (blue circle). The scale bar is 10 µm. b Galvanostatic characteristics, obtained using an applied (dis)charge current of (−)+1.2 nA (shown in green). The resulting voltage curves are shown in red, taken within fixed limits of 1.0 V and 2.9 V. c Cross-plane thermal conductance measured during the electrochemical cycle shown in b. d Circuit diagram of the thermal transistor device: the gating voltage V_WE) that is applied between Li and Al/MoS₂ electrodes changes the thermal conductance G) to heat flow between the Al transducer and SiO₂ substrate, which are at temperatures T_Al and T_SiO2 respectively. e Thermal conductance and average lithium composition χ plotted vs. voltage, showing significant hysteresis between charge and discharge curves. f G plotted against χ