Nitrogen and fluorine co-doped graphene as a high-performance anode material for lithium-ion batteries

Abstract

Supplementary InformaƟon (ESI) available: FT-IR spectrum, Raman spectrum, XRD patterns, XPS survey spectra, TEM and SEM images, the first three CV curves, Cycle performance, and rate capabilities of NG and RGO See Nitrogen and fluorine co-doped graphene (NFG) with the N and F content as high as 3.24 and 10.9 at.% was prepared through the hydrothermal reaction of trimethylamine tri(hydrofluoride) [(C2H5)3N·3HF] and aqueous-dispersed graphene oxide (GO) as the anode material for lithium ion batteries (LIBs). The N and F co-doping in graphene increased the disorder and defects of the framework, enlarged the space of the interlayer, wrinkled the nanosheets with many open-edge sites, and thus faciliated Li ion diffusion through the electrode compared with sole-N or F doped graphene. X-ray photoelectron spectroscopy (XPS) analysis of NFG demonstrated the presence of active pyridine and pyrrolic types N, and highly electrical conductive graphitic N and semi-ionic C-F bond in the structure. The N and F doping content and the component types of N and F functional groups could be controlled by the hydrothermal temperature. The NFG prepared at 150°C exhibited the best electrochemical performances tested as the anode of LIBs, including the high coulombic efficiency in the first cycle (56.7%), superior reversible specific discahrge capacity (1075 mAh g −1 at 100 mA g −1 ), excellent rate capabilities (305 mAh g −1 at 5 A g −1 ), and outstanding cycling stability (capacity retention of ~95% at 5 A g −1 after 2000 cycles), which demonstrated NFG was a promising candidate for anode materials of high-rate LIBs. 18,20,25 Recently, it has been realized that doping graphene with two or more kinds of heteroatoms can further improve its electrochemical performances because Li-ion storage is not only related with the contents of heteroatoms but also with

Fluorination of MXene by Elemental F2 as Electrode Material for Lithium‐Ion Batteries

“…They correspond to surface F at different densities. It has also been reported that these peaks are attributed to semi‐ionic (F LD −C) and covalent (F HD −C) C−F bonding . An additional peak is found in the FMX3 spectrum at a higher BE of 689.4 eV attributed to CF 2 as is also seen from the C 1s spectrum (see Figure a) .…”

“…The spectrum from the FMX24 sample shows only two peaks that are related to Ti−O−F bonds and covalently bonded F with a high surface coverage. With higher fluorination times it is confirmed that the samples start to be dominated by two types of F, the Ti−O−F bond and densely packed covalently bonded F (F HD −C) …”

Reduced graphene oxide enwrapped phosphors for long-term thermally stable phosphor converted white light emitting diodes

“…A clear difference in the diffraction patterns is observed for those recorded from the rGO (edges) as well as from the phosphor regions (inner region) of the rGO wrapped phosphor particles. The SAED pattern recorded from the inner regions correspond to the phosphor21 while the SAED pattern recorded from edges correspond to rGO222324.…”

Critical Insight into the Relentless Progression Toward Graphene and Graphene‐Containing Materials for Lithium‐Ion Battery Anodes

“…Other kinds of graphene also proved their strength upon long term cycling. Indeed, N-doped RGO, [ 95 ] porous RGO aerogel, [ 96 ] N-doped 3D macroporous RGO, [ 97 ] N-doped graphene (synthesized by bottom-up procedure), [ 98 ] N-S-codoped RGO, [ 99 ] N-F-codoped RGO, [ 100 ] N-doped holey RGO foam, [ 101 ] and porous graphene (obtained by a peculiar top-down process) [ 102 ] displayed some of the most promising electrochemical performances among all graphene-based anodes (Table 1 ). Interestingly, it was also proved that multilayer graphene (obtained by liquid-phase exfoliation in 1-ethyl-3-methylimidazolium acetate ionic liquid) could reversibly store lithium ions down to −30 °C, showing noticeable specifi c gravimetric capacity even when directly compared to its graphite analogue.…”