A Roadmap for Achieving Sustainable Energy Conversion and Storage: Graphene-Based Composites Used Both as an Electrocatalyst for Oxygen Reduction Reactions and an Electrode Material for a Supercapacitor

Abstract

Based on its unique features including 2D planar geometry, high specific surface area and electron conductivity, graphene has been intensively studied as oxygen reduction reaction (ORR) electrocatalyst and supercapacitor material. On the one hand, graphene possesses standalone electrocatalytic activity. It can also provide a good support for combining with other materials to generate graphene-based electrocatalysts, where the catalyst-support structure improves the stability and performance of electrocatalysts for ORR. On the other hand, graphene itself and its derivatives demonstrate a promising electrochemical capability as supercapacitors including electric double-layer capacitors (EDLCs) and pseudosupercapacitors. A hybrid supercapacitor (HS) is underlined and the advantages are elaborated. Graphene endows many materials that are capable of faradaic redox reactions with an outstanding pseudocapacitance behavior. In addition, the characteristics of graphene-based composite are also utilized in many respects to provide a porous 3D structure, formulate a novel supercapacitor with innovative design, and construct a flexible and tailorable device. In this review, we will present an overview of the use of graphene-based composites for sustainable energy conversion and storage.

Vitamin Derived Nitrogen Doped Carbon Nanotubes for Efficient Oxygen Reduction Reaction and Arsenic Removal from Contaminated Water

“…Amongst these, iron nano-particles that are embedded in nitrogen doped conductive carbon nanostructures have aroused tremendous interest due to its excellent catalytic activity. These kinds of non-precious metal/nitrogen doped carbon nano-material systems are fast emerging as the most probable replacement for the expensive and inefficient commercial Pt/C ORR catalysts [9,10]. Theoretical calculations [11] and experimental studies have both shown that the presence of metal-nitrogen (M-N x ) complexes embedded in conductive carbon skeleton is critical factor in obtaining high electrocatalytic activity in ORR.…”

Ammonium Nitrate-Assisted Synthesis of Nitrogen/Sulfur-Codoped Hierarchically Porous Carbons Derived from Ginkgo Leaf for Supercapacitors

“…It is found that the incorporation of N and S increases electrical conductivity, electrocatalytic activity, and wettability of the electrode and contributes to pseudocapacitances. 38−41 In this work, we demonstrated a one-step process for the synthesis of N/S-codoped hierarchically porous carbons (NSHPCs) with GL and AN as a carbon source and an activating agent, respectively. The as-synthesized NSHPCs with 3D interconnected hierarchically porous structures displayed a large specific surface area and excellent capacitance performance with high energy and power density.…”

“…The dry GL is composed of about 45.1% carbon, 34.0% oxygen, 1.2% nitrogen, 0.7% sulfur, 5.5% hydrogen, and 13.4% ash. , The relatively higher content of N and S compared to that in other biomass such as coconut sheath and corn stover indicates that the GL-derived porous carbons can be self-doped with N and S heteroatoms. It is found that the incorporation of N and S increases electrical conductivity, electrocatalytic activity, and wettability of the electrode and contributes to pseudocapacitances. − In this work, we demonstrated a one-step process for the synthesis of N/S-codoped hierarchically porous carbons (NSHPCs) with GL and AN as a carbon source and an activating agent, respectively. The as-synthesized NSHPCs with 3D interconnected hierarchically porous structures displayed a large specific surface area and excellent capacitance performance with high energy and power density.…”

Fluorinated Graphene Prepared by Direct Fluorination of N, O-Doped Graphene Aerogel at Different Temperatures for Lithium Primary Batteries

“…Graphene-based materials have attracted great attention in nanotechnology because of their amazingly attractive properties, such as high theoretical specific surface area (2630 m 2 g −1 ), superior electron mobility, easy self-assembling into three-dimensional (3D) macroscopic materials with controlled microstructures, high mechanical, chemical, thermal, and electrochemical stabilities, etc. Therefore, graphene-based materials have already been widely applied in many fields, including but not limited to nanoelectronics [ 1 ], energy storage and conversion [ 2 , 3 ], sorption/separation [ 4 ], water purification [ 5 ], sensor [ 6 ], etc. However, pristine graphene suffers from several shortcomings, including a zero bandgap and structural defects chemical inertness.…”