Synthetic Methodologies and Energy Storage/Conversion Applications of Porous Carbon Nanosheets: A Systematic Review

Abstract

Owing to their unique morphologies, properties, and promising applications, two-dimensional (2D) porous carbon materials have attracted tremendous research interest in the past decade. These materials not only combine the advantages of both 2D and porous structures but also possess some excellent features, including nanoscale thickness, high surface area, and enhanced electronics, heat, and mass transport properties bestowing them with high potential for applications in energy storage, catalysis, and adsorption. 2D Porous carbon nanosheets (2D PCNS) have been extensively investigated since the explosive research on graphene. The key factor for the target application of these materials is their porous morphologies which are greatly affected by various synthetic procedures. This review focuses on the recent progress in synthetic methodologies for 2D PCNS, in which the main porosity controlling factors for each method are highlighted. Applications of such materials are discussed in detail in energy storage and conversion devices, including supercapacitors, lithium, sodium, potassium, and zinc-ion batteries, lithium–sulfur batteries, and heterogeneous catalysis. Finally, the challenges and prospects of the further development of 2D PCNS are discussed.

Review and Perspectives of Sustainable Lignin, Cellulose, and Lignocellulosic Carbon Special Structures for Energy Storage

“…22 A review by Kasprzak et al highlighted different composites of polysaccharide-derived carbons with lignocellulose for flexible energy storage devices. 23 Lignocellulosic carbon and their composites with conductive polymers and other carbon-based materials like graphene, 24 carbon nanosheets, 25 etc. have been reported.…”

Overview of the Latest Developments and Perspectives about Noncarbon Sulfur Host Materials for High Performance Lithium–Sulfur Batteries

“…The discharge process of the battery can be simply expressed as The charge process of the battery is a reverse process of the discharging reaction and is similar to the discharge process . Two plateaus can be seen from the charge curve, and the specific charge process can be divided into the following two steps (Figure (b)): (6) The first charging long plateau corresponds to Li 2 S/Li 2 S 2 being electrochemically oxidized to LiPS (Li 2 S x , 4 ≤ x ≤ 8) ,, and over again into the electrolyte .…”

“…The charge process of the battery is a reverse process of the discharging reaction and is similar to the discharge process. 30 Two plateaus can be seen from the charge curve, and the specific charge process can be divided into the following two steps (Figure 1(b)): (6) The first charging long plateau corresponds to Li 2 S/Li 2 S 2 being electrochemically oxidized to LiPS (Li 2 S x , 4 ≤ x ≤ 8) 29,31,32 and over again into the electrolyte. 20 (7) The second short charging plateau corresponds to the LiPS being further oxidized into elemental sulfur and redeposited on the cathode.…”

“…2 2 8 (7) Compared with traditional LIBs, Li−S batteries have many advantages and may even become the main development direction in the future. 30 This is mainly because of the following: Sulfur has a low price, abundant reserves, and exists as a simple substance in nature. 33 Also, sulfur has a high energy density and is environmentally friendly.…”

“…18 Second, a large change in the volume of sulfur is also one of its problems. In the process of continuous charging and discharging, 30 volumetric expansion not only destroys the structure of the cathode material but also brings shedding of the active material, 39 which affects the integrity of the battery structure and the transfer of electrons and also leads to reduced life of the battery. In the charging and discharging process, 40 there are LiPSs intermediate products produced and easily dissolved in the electrolyte, 31 which will cause the Li−S battery capacity to decay quickly.…”