Fabrication of large-area and high-crystallinity photoreduced graphene oxide films via reconstructed two-dimensional multilayer structures

Abstract

Graphene, the last representative sp 2 carbon material to be isolated, acts as an ideal material platform for constructing flexible electronic devices. Exploring a new method to fabricate high-quality graphene films with high throughput is essential for achieving greater performance with flexible electronic devices. Here, we report a facile coating and subsequent illumination method for mass-fabricating highly crystalline photoreduced graphene oxide (PRGO) films directly onto conductive substrates. The direct fabrication of PRGO films onto Cu foils with partial oxygenated groups, an intensive stacked highly crystalline structure, and reduced graphene oxide regions enable significant performance enhancements when used as supercapacitor electrodes compared with other graphene-only devices, exhibiting high specific capacitances of 275 F g À1 at a scan rate of 10 mV s À1 and 167 F g À1 at 1 V g À1 with excellent rate capability. The as-established all-solid-state flexible supercapacitors exhibit superior flexibility and robust mechanical stability, resulting in a capacitance delay of only 2% after performing 100 bending cycles. The demonstrated PRGO films provide a promising material platform to realize a broad range of applications related to flexible electronics devices. INTRODUCTIONFlexible electronic devices have garnered considerable attention because of the benefits enabled by large-area, lightweight, flexible electrode films, which have the potential to enable unique advances in future mobile applications, such as wearable displays, roll-up solar cells, electronic skin and flexible energy storage. 1,2 Graphene films containing a few layers or multiple layers of two-dimensional graphene sheets are prominent contenders as attractive components for use in flexible electronic devices due to their high conductivity, chemical stability and mechanical flexibility. 3,4 For the practical applications of graphene in these fields, scalable production of macroscopic-scale graphene films is required rather than the current micrometer-sized graphene sheets. To date, the synthesis of large-scale flexible graphene films has mainly been demonstrated by two approaches. One approach is the 'bottom-up' synthesis strategy, by which high-quality graphene can be prepared using chemical vapor deposition to grow graphene at high temperature, followed by a transfer procedure to place graphene films onto flexible substrates; 5 however, this method is not sufficiently cost-and time-effective to be commercially viable for mass production and requires a difficult post-functionalization step to produce the appropriate graphene films. Another approach is the 'top-down' method, that is, solution

Physicochemical properties and performance of graphene oxide/polyacrylonitrile composite fibers as supercapacitor electrode materials

“…7,20,21 The specic capacitances of graphene-based SC electrodes range from 270 to 310 F g À1 . 22,23 Electrodes with specic capacitances ranging from 214 to 374 F g À1 have been successfully fabricated using graphene derived from biomass, including coconut shells, wood, rice husks, walnut shells, banana peels, bagasse, tea leaves, bamboo, palm oil waste, and palm kernel shells. 19,[24][25][26][27] However, few nanober-based rGOPKS electrodes have been developed.…”

MoS2/C/C nanofiber with double-layer carbon coating for high cycling stability and rate capability in lithium-ion batteries

“…At the same time, carbon materials can also act as a binder between the S/Li 2 S and the molybdenum to prevent the loss of polysulfide during cycling [1,23,27,28]. Based on these properties, hybrid MoS 2 -carbon systems can lead to better electrode kinetics and more stable cycling performance [29][30][31][32][33].…”

3D Freeze‐Casting of Cellular Graphene Films for Ultrahigh‐Power‐Density Supercapacitors

“…[ 12 ] In these situations, a large amount of energy needs to be either stored or delivered in highpower-density energy-storage devices. A number of methods, such as blade-coating, [ 17 ] spray-coating, [ 18 ] layer-by-layer assembly, [ 19 ] interfacial selfassembly, [ 20 ] and fi ltration assembly [ 21,22 ] have been developed to fabricate graphene fi lms. Owing to its extraordinary properties, such as high electrical conductivity as well as high specifi c surface area, and a wide stable potential window, graphene, a one atom-thin 2D fl ake of carbon, holds great promise as a high-performance electrode material for supercapacitors.…”