Vertically-Oriented Graphene for Other Energy Storage and Conversion Applications

Vertically-oriented graphenes (VGs) have outstanding electrical conductivity, robust binding with the substrate, and high chemical tolerance in electrolytes. These features of VGs offer great promise in electrochemical energy storage and conversion devices. Following our discussion in the previous chapter on the application of VGs as the electrode materials in supercapacitors, in this chapter we introduce the potential of VGs in other energy storage and conversion devices, specifically, rechargeable batteries, fuel cells, and dye-sensitized solar cells (DSSCs). Without the use of any binder and conductive additives, VGs grown on current collectors (e.g., metal foils) can directly serve as the anode in lithium-ion batteries (LIBs) and the electrode in vanadium redox flow batteries (VRFBs), which can significantly simplify the battery manufacturing process. More important, batteries using VG electrodes have shown improved performance. For energy conversion applications, VGs can be used in fuel cells and DSSCs. The unique features of VGs make them an ideal catalyst support for anode reactions in a fuel cell. In addition to working as the catalyst support, VGs with a controlled number of oxygen functional groups can work as catalysts themselves for DSSCs.