Highly thermally conductive graphene-based electrodes for supercapacitors with excellent heat dissipation ability

Abstract

Efficient heat dissipation is a crucial issue for electrochemical energy storage devices like supercapacitors. A large amount of heat is generated during the charging and discharging processes, especially at high current densities. This significantly accelerates capacity fading and serious safety problems such as explosions might occur for energy storage devices, and it can also cause human discomfort and even skin burns for wearable electronic or implantable electronic devices if the heat does not dissipate efficiently. In this contribution, highly thermally conductive electrodes based on graphene–MnO₂ films are developed, which demonstrate high thermal conductivity of 613.5 W m⁻¹ K⁻¹ relative to that of 1.1 W m⁻¹ K⁻¹ of the traditional MnO₂ slurry electrodes. The high thermal conductivity film electrode-based supercapacitor not only exhibits excellent heat dissipation ability during the charging and discharging processes, which is beneficial for the thermal management of supercapacitor devices, but also good cycling performance and excellent rate capacity for a high specific capacity of about 218.8 F g⁻¹ at a high current density of 10 A g⁻¹.