Energy Conversion and Storage in Fuel Cells and Super-Capacitors from Chemical Modifications of Carbon Allotropes: State-of-Art and Prospect

Abstract Despite being generated from the same element and having some of the properties commonly shared, each type of carbon allotrope possessing divergent shape confers unique and distinguishable physicochemical properties, thereby making them attractive for a wide range of potential applications. Moreover, research progress has allowed for further tailoring the properties in a controlled way to design more fascinating and aesthetically pleasing architectures with outstanding materials properties. In fact, some chemically modified carbon allotropes and their products have shown significant promise to solve a number of major issues in polymer exchange membrane fuel cells (PEMFCs) and supercapacitors (SCs) such as efficient low Pt loaded oxygen reduction reaction (ORR) catalysts, carbon allotrope-based proton conductors for PEMFC electrolyte, carbon monoxide (CO) tolerant anode catalysts for PEMFC, and carbon allotropes-based SC electrodes. The tremendous progress made in carbon-based materials facilitates those technologies more realistically towards large-scale implementation in terms of increasing the stack power density and reducing cost. In this view, this review will provide a thorough insight for researchers into the use of carbon allotropes and relevant products for PEMFCs and SCs.