Scalable Fabrication Of Free-standing Graphene Nanomesh Films For Flexible Thin-film Supercapacitors With AC Line-filtering Performance

As a new energy storage device,supercapacitors are widely used in energy storage.In the field of AC linear filtering,aluminum electrolytic capacitors(AECs)have been used as the only commercial capacitor.Aluminum electrolytic capacitors as a common capacitor,there is bulky,low energy density and other shortcomings,is not suitable for the flexible electronics.Due to its high specific surface area,excellent electrochemical properties and good mechanical properties,graphene is expected to be the most promising material for the next generation of supercapacitors.In this paper,graphene oxide was used as a precursor to fabricate an ultra-thin graphene film with controlled thickness by in-situ assembly on the surface of metal sheets(Ni,Co,Fe).Due to the oxidation of the metal during the reduction,the metal oxide nanoparticles are uniformly formed on the graphene sheet.In an inert atmosphere,by controlling the different annealing temperature,the carbon-thermal reaction between metal and graphene is used to form nanopores in the graphene sheet.In summary,a thin-film nanosilver thin film with controlled thickness and adjustable aperture can be prepared on a large scale.The ultrathin graphene nanowhisker film was used as an electrode for the preparation of supercapacitors.The ultrathin graphene nanomesh film had a capacitance of 7.6 F cm-3 and a power density of 3000 W cm-3 at 120 Hz.More importantly,this ultra-thin graphene nanomesh film has a phase angle of-82.3° at 120 Hz and an RC time constant of 0.32 ms,with superb cycling stability.The phase angle remains 98% after 50,000 cycles.Compared with other similar materials used in AC linear filtering,the electrochemical performance of ultrathin graphene prepared in this paper is in a leading position.In order to further explore this graphene nanoscale thin film in the AC linear filter applications.In this paper,graphene films with different thickness(150nm,200 nm,450nm)were prepared by controlling different reaction times,and different nanopores were prepared by controlling the annealing temperature(300 ?,500 ?,700 ?)The effects of thickness and annealing temperature on AC linear filtering were investigated.As the film thickness increases,the phase angle value(120 Hz)has been decreasing,but its capacitance has been increasing.As the temperature increases,the size of the pores in the graphene film increases and the capacitance decreases,but the phase angle increases.In addition,the electrochemical properties of device was further explored in all-solid electrolytes,which have paved the way for their application in the field of flexibility.In the end,through the series-parallel test proved that the consistency of the material is very high,to explore the possibility of its commercialization.