Hierarchical Interconnected Expanded Graphitic Ribbons Embedded with Amorphous Carbon: An Advanced Carbon Nanostructure for Superior Lithium and Sodium Storage

Abstract

Carbon materials have attracted considerable attention as anodes for lithium-ion and sodium-ion batteries due to their low cost and environmental friendliness. This work reports an advanced carbon nanostructure that takes advantage of the chelation effect of glucose and metal ions, which ensures the uniform dispersion of metal in the precursor. Thus, an effective catalytic conversion from sp to sp carbon occurs, enabling simultaneously formation of pores with catalyzed graphitic structures. Due to the low carbonization temperature and short carbonization time as well as the different catalytic degree of various metals, a series of expanded graphitic layers from 0.34 to 0.44 nm with defects and amorphous carbon structure are obtained. The structure not only offers accessible graphitic spacings for reversible lithium/sodium ion insertion, but also provides abundant active sites for lithium/sodium ion adsorption in the defects and amorphous structure. Moreover, the hierarchical interconnected porous structure combining graphitic ribbons is beneficial for fast electronic/ionic transport and favorable electrolyte permeation. More importantly, such advanced carbon materials prove their feasibility for balancing the pore structure and degree of graphitization. When serving as the electrode material for lithium-ion and sodium-ion batteries, excellent electrochemical performance along with fast kinetics and long cycle life is achieved.

3D Oxygen‐Defective Potassium Vanadate/Carbon Nanoribbon Networks as High‐Performance Cathodes for Aqueous Zinc‐Ion Batteries

“…The micropores in amorphous carbon can also be identified, which would serve as adsorption sites for zinc ions. [42] The homogenous distributions of C, K, V, and O elements in C-KVO|O d are confirmed by elemental mapping images in Figure 2f-i. By contrast, in the pure KVO samples calcinated in air atmosphere ( Figure S2, Supporting Information), there are only thick rods with diameter of about 500 nm.…”

“…The micropores in amorphous carbon can also be identified, which would serve as adsorption sites for zinc ions. [42] The homogeneous distributions of C, K, V, and O elements in C-KVO|O d are confirmed by elemental mapping images in Figure 2f This crystal structure is formed by the vanadate framework containing VO 5 pyramids and VO 6 octahedron, in which K + ions are inserted in the tunnel structure. The diffraction peaks of the C-KVO|O d sample are less intense than those of the pure KVO ( Figure S3), which verifies the decreased crystallinity of the C-KVO|O d after the calcination in inert atmosphere.…”

“…In addition, the peaks at 1325 and 1593 cm -1 correspond to the D (defect) band and G (graphite) band of carbon, respectively. [42] XPS measurements were conducted to further confirm the chemical state of the C-KVO|O d , as displayed in Figure 3c-e. The C 1s spectrum of the C-KVO|O d in Figure 3c are deconvoluted into three peaks of C-C, C-O, and C=O, demonstrating the existence of carbon with some oxygen-containing functional groups.…”

“…In addition, the peaks at 1325 and 1593 cm −1 correspond to the D (defect) band and G (graphite) band of carbon, respectively. [42] X-ray photoelectron spectroscopy (XPS) measurements were conducted to further confirm about 6 wt%, as determined by thermogravimetric measurement ( Figure S4, Supporting Information). In Figure 3d, the O 1s spectrum of the C-KVO|O d is deconvoluted into four peaks located at 530.1, 531.5, 532.2, and 533.2 eV, which correspond to the V-O bond, oxygen defects, bridge-bonded oxygen (O-H, O-C), and carbonyl groups (C=O), respectively.…”

Double-layer carbon protected CoS2 nanoparticles as an advanced anode for sodium-ion batteries

“…The GC originating from the catalysis of Co nanocrystals during the thermal treatment can improve the electrical conductivity and prevent the agglomeration of CoS 2 nanoparticles. [22][23][24][25] The elemental mapping images (Fig. 2f) further demonstrate that the CoS 2 nanoparticles were encapsulated in B-CNT.…”