Preparation Of Silver Nanowire-Based Composites And Its Application In Flexible Transparent Supercapacitors

With the rapid development of transparent and flexible electronic devices,their energy conversion and storage systems not only require large power/energy density,but also put forward high transparency and flexibility demands.Transparent and flexible supercapacitors?TFSs?as one of the ideal energy storage devices is the most promising to be realized by guaranteeing the transparency and flexibility of the electrodes and electrolyte.We investigated the supercapacitors based on the flexible and transparent silver nanowire?Ag NW?current collector.The main research contents are listed as follows:?1?Ag NW/graphene composite films were fabricated on polyethylene terephthalate?PET?substrates using an electrophoresis method,making graphene sheets closely contact with NW networks.As electrophoresis voltage increased from-1V to-10 V,the transmittance and sheet resistance of the composite film changed in the range of 64.8%-35.2%and 0.98?/sq-6.61?/sq?initial values are 75.7%and 0.77?/sq?.Combing the advantages of two materials,the stability of the Ag NW film was greatly enhanced due to protection of the graphene layer,and the conductivity of the graphene electrode was remarkably improved ascribed to introduction of the interconnected networks.The areal and specific capacitance of the composite film increased from 1.22 mF/cm² to 7.6 mF/cm² and decreased from 108.4 F/g to 25.7 F/g at100 mV/s in a 1M LiClO₄ solution,as the electrophoresis voltage increased from-1 V to-10 V.Furthermore,the Ag NW/graphene composite film exhibited a good long-term cycling stability with 82.6%capacitance retention after 2500 cycles.?2?Flexible and transparent electrodes based on one-dimensional Ag NW@NiCo/NiCo?OH?₂ core-shell nanostructures with tunable composition were fabricated by electrodeposition.The highly conductive Ag NW network was considered as the current collector,and the NiCo/NiCo?OH?₂ nanostructures could grow on the surface of the Ag NWs,providing active materials with the synergistic effect of Ni and Co element.The core-shell nanostructures integrate the advantages of metallic NWs for effective charge transport,NiCo alloyed layer for stable structure,and NiCo?OH?₂ for high electrochemical performance.The composite electrode with a transmittance of 54.3%delivers a high areal capacitance of 22.2 mF/cm² at a current density of 0.1 mA/cm²,and an excellent capacitance retention rate of 91.9%at 100mV/s after 5000 cycles.?3?Asymmetric supercapacitor with Ag NW/graphene electrode was assembled in this work.The power density of the symmetrical supercapacitor was 0.52 W/kg,with the energy density of 0.142 Wh/kg,the potential window of 0.8 V,and the transmittance of 24.0%.It also showed good flexibility.We further assembled Ag NW@NiCo/NiCo?OH?₂?Ag NW/graphene asymmetric supercapacitor using Ag NW/graphene as electrode materials.Under the current density of 0.2 mA/cm²,the highest energy density of 3.0 W/kg,the largest power density of 3.5 W/kg,and the specific capacitance of 9.6 mF/cm² are achieved.The transmittance of the device was increased to 36.2%,and the potential window was extended to 1.2 V.The investigations suggest that the transparent and flexible electrodes based on the Ag NW conducting network have great potential in flexible and transparent energy storage devices.