Simple Preparation of Carbon Nanofibers with Graphene Layers Perpendicular to the Length Direction and the Excellent Li-Ion Storage Performance

Abstract

Sulfur-containing carbon nanofibers with the graphene layers approximately vertical to the fiber axis were prepared by a simple reaction between thiophene and sulfur at 550 °C in stainless steel autoclaves without using any templates. The formation mechanism was discussed briefly, and the potential application as anode material for lithium-ion batteries was tentatively investigated. The carbon nanofibers exhibit a stable reversible capacity of 676.8 mAh/g after cycling 50 times at 0.1 C, as well as the capacities of 623.5, 463.2, and 365.8 mAh/g at 0.1, 0.5, and 1.0 C, respectively. The excellent electrochemical performance could be attributed to the effect of sulfur. On one hand, sulfur could improve the reversible capacity of carbon materials due to its high theoretical capacity; on the other hand, sulfur could promote the formation of the unique carbon nanofibers with the graphene layers perpendicular to the axis direction, favorable to shortening the Li-ion diffusion path.

X‐Ray Spectromicroscopy Investigation of Heterogeneous Sodiation in Hard Carbon Nanosheets with Vertically Oriented (002) Planes

“…Previously, engineering graphene layer orientation to achieve high rate capability has been demonstrated for LIB graphitic anode. [ 14,50 ] Similar to the diffusion mechanism of lithium‐ion in graphite, [ 51 ] the insertion–extraction of sodium ions is expected to occur from the edge planes. Therefore, with a higher proportion of (002) planes oriented vertically to the sheet surface, the increased contact between the edge planes and the electrolyte would facilitate the insertion–extraction of sodium ions in the VOHCs.…”

Plasmachemical Synthesis of Nanodispersed Silicon Powder and Its Use As Anode in Lithium-Ion Battery

“…Currently, the anode material of LIBs, in most cases, is graphite, which has a theoretical specific capacity of 372 mAh/g and high cyclic stability. The desire to improve the performance of LIBs leads to the study of alternative materials and additives as anodes: nanoscale allotropic modifications of carbon [1][2][3], a combination of carbonaceous materials with different materials having an increased specific capacity, such as silicon, tin, germanium, manganese, zinc and their oxides [5][6][7][8][9][10][11]. The most promising anode material is considered to be silicon, due to the high theoretical specific capacity-4200 mAh/g, for compound Li4.4Si (Li22Si5).…”

Doping-template approach of porous-walled graphitic nanocages for superior performance anodes of lithium ion batteries

“…Lithium ion batteries (LIBs) are commercially successful energy storage devices, due to their high energy density, high operating voltage and long cycle life. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Its low cost, good electronic conductivity, moderate operation voltage and stability enable graphite to be the dominant anode material for the current LIBs, leading to many novel anodes prepared from advanced graphitic nanomaterials, such as carbon nanotubes (CNTs), 5,6 nanobers (CNFs), 7 nanocages 2, [9][10][11][12][17][18][19][20] and graphenes, [13][14][15][16]21,22 drawing great attention. However, their performance is still far from satisfactory, especially at a high charge-discharge rate ($0.5 A g À1 ), as graphite has a lower theoretical capacity of 372 mA h g À1 .…”

“…However, their performance is still far from satisfactory, especially at a high charge-discharge rate ($0.5 A g À1 ), as graphite has a lower theoretical capacity of 372 mA h g À1 . [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] It should be noted that achieving high capacities at elevated charge/ discharge rates is particularly challenging since the time available for ions to diffuse through the anode and intercalate is now signicantly shorter. 13,22 Chemical doping is an effective strategy to enhance such performance by increasing electronic conductivity or active sites for Li + storage.…”

“…[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] It should be noted that achieving high capacities at elevated charge/ discharge rates is particularly challenging since the time available for ions to diffuse through the anode and intercalate is now signicantly shorter. 13,22 Chemical doping is an effective strategy to enhance such performance by increasing electronic conductivity or active sites for Li + storage. 7,10,[12][13][14]20 Additionally, photothermal-reduced graphene was reported to increase Li + diffusion channels by creating micrometerscale open-pore structure in the graphene anodes.…”