NiMn hydroxides supported on porous Ni/graphene films as electrically and thermally conductive electrodes for supercapacitors

Solid-state supercapacitors (SSCs) hold great promise in the application in portable and wearable electronic devices due to their great progress in electrochemical performance and fabrication technique in recent years. However, in consideration of increasingly harsh requirements toward electronic devices in miniaturization and operational security, the management of thermal generation and dissipation in SSC devices, which have been rarely considered at present, are very worthwhile to be investigated. In this work, flexible solid-state supercapacitors are assembled by rationally designed electrodes, which are fabricated layer by layer by using of an electrochemically exfoliated graphene (EG) nanosheet film, a porous metallic Ni layer and a NiMnLDH pseudocapacitive material layer. The ultrathin NiMnLDH nanosheets and the porous metallic Ni layer ensure high electrochemical performance for the NiMnLDH/Ni/EG electrodes (2110.4 mF cm(-2)) and the assembled SSC energy storage devices (732.5 mF cm(-2)). The employments of the EG film and the Ni layer avoid the SSC energy storage devices suffering from overheating during operation, because the high thermally conductive EG film could effectively dissipate the heat generated in the energy storage devices and the high electrically conductive metallic Ni layer could achieve low internal resistance to alleviate the Joule heat generation in the devices. This work could provide an effective thermal management strategy to promote future application of high-power energy storage devices in electronic industry.