Structural Evaluation of Coal-Tar-Pitch-Based Carbon Materials and Their Na+ Storage Properties

Abstract

Linking to the S element hybrid strategies, S-doped carbon materials having different macrostructures and defect concentrations are prepared by using sulfur and coal-tar-pitch as raw materials in a carbonization temperature range of 700–1000 °C. The evaluations of macrostructure and surface characteristics are performed through XRD, TEM, Raman and XPS measurements. Through the linear fitting among the Na+ storage capacity with ID/IG and d002 values, the correlations of Na+ storage capacity with macrostructures and defects are respectively investigated in detail. It is observed that S-doped carbon materials exhibit storage capacity at 120 mAh/g after the charge-discharge is being carried out 2000 cycles at 2.0 A/g. Studies have shown that adsorptions of introduced defects on graphene-like carbon sheets mainly play the role to enhance the storage capacity, and the expanded carbonaceous lamellar spaces of highly disordered and pseudo-graphitic macrostructures provide the channels for fast transfer of Na+. Our studies are able to provide references for designs and fabrications of coal tar pitch based soft carbon materials as sodium-ion batteries (SIBs) anodes when using heteroatoms doping methods.

Coal-Based Electrodes for Energy Storage Systems: Development, Challenges, and Prospects

“…51 With the increasing radii of heteroatoms, the S-doped carbon showed a larger interlayer distance (0.394 nm). 52 Moreover, the presence of −C−S x −C and −C−SO x −C groups induced the enhancement of pseudocapacitive behaviors. At 3.0 mV s −1 , the ratio of capacitive contributions increased up to 74%, further providing an in-depth understanding of charge-storage behaviors.…”

“…60 To further introduce nitrogen elements, NH 3 and N 2 gases have been added during the sintering process of coal, successfully forming the N-doped samples, accompanied by increased interlayer distances and obviously enhanced pseudocapacitive behaviors as shown in Figure 6e,f. 52,61 Moreover, it should be acknowledged that introducing conductive carbon matrices (CNTs and graphene) usually improves their energy storage abilities. For instance, 3D graphite microcrystals were obtained from natural coal with plentiful oxygen groups.…”

“…Zhao’s group prepared O-doped carbon, where the distance was enlarged from 0.344 to 0.384 nm, resulting in an improved capacity (360 mA h g –1 at 0.05 A g –1 after 100 cycles) . With the increasing radii of heteroatoms, the S-doped carbon showed a larger interlayer distance (0.394 nm) . Moreover, the presence of −C–S x –C and −C–SO x –C groups induced the enhancement of pseudocapacitive behaviors.…”

“…Schematic illustration of modified pitch-derived carbon frameworks (a), SEM images and TEM images of MCF; pseudocapacitive contributions at various scan rates (e,f); or different metamorphic-grade coal, Raman Mapping (g), mechanism of sodium-ion storage (h), and surface-controlled contribution (i) …”

High-performance aqueous rechargeable nickel//bismuth batteries with Bi2MoO6@rGO and Co0.5Ni0.5MoO4@rGO as electrode materials

“…[1][2][3][4][5][6][7][8] Among the assorted energy-storage devices, commercialized lithium-ion batteries have been widely applied in our daily lives in view of their various merits, such as high energy density, no memory, high voltage, and small self-discharge. 7,[9][10][11][12][13][14] Nevertheless, the limited lithium reserves, stringent requirements for battery assembly, and especially, safety risks associated with the toxicity and flammability of organic electrolytes cannot be ignored. For instance, incidents including the Tesla Model S combustions in 2019, Samsung Note 7 explosions in 2016, and Boeing 787 battery fires in 2013 all posed serious threats to human life and property safety.…”