Efficient thermal protection is of great significance for electronic devices. Herein, we demonstrate a novel thermoswitchable microsupercapacitor (TS-MSC) with the self-protection function utilizing the thermodynamic behavior of a smart electrolyte, a lithium salt–dissolved polymer sol, poly(N-isopropylacrylamide)-g-methylcellulose. Benefiting from the reversibility of ionic conductivity, the TS-MSC exhibited a broad temperature window (30–80 °C) and totally switch-off behavior at 80 °C, as well as excellent cycling stability upon heating/cooling cycles. In addition, the thermal protection of on-chip integrated MSCs in series or parallel was achieved by controlling a single TS-MSC connected with a computer CPU under different working conditions. Therefore, TS-MSCs are promising components in the thermal protection of practical on-chip electronic devices.