A Promising Carbon/g‐C₃N₄ Composite Negative Electrode for a Long‐Life Sodium‐Ion Battery

Abstract

2D graphitic carbon nitride (g-C 3 N 4 )nanosheets are ap romising negative electrode candidate for sodium-ion batteries (NIBs) owing to its easy scalability,low cost, chemical stability,and potentially high rate capability.However,intrinsic g-C 3 N 4 exhibits poor electronic conductivity,l ow reversible Na-storage capacity,a nd insufficient cyclability.D FT calculations suggest that this could be due to al arge Na + ion diffusion barrier in the innate g-C 3 N 4 nanosheet. Afacile onepot heating of am ixture of low-cost urea and asphalt is strategically applied to yield stackedm ultilayer C/g-C 3 N 4 composites with improved Na-storage capacity (about 2times higher than that of g-C 3 N 4 ,upto254 mAh g À1 ), rate capability, and cyclability.AC/g-C 3 N 4 sodium-ion full cell (in which sodium rhodizonate dibasic is used as the positive electrode) demonstrates high Coulombic efficiency (ca. 99.8 %) and anegligible capacity fading over 14 000 cycles at 1Ag À1 .

DFT-Guided Design and Fabrication of Carbon-Nitride-Based Materials for Energy Storage Devices: A Review

“…DFT studies of pure carbon nitrides for large-sized metal ion batteries have also been reported. For instance, Weng et al showed that pure C 3 N 4 nanosheet displays high adsorption energy for Na-atom, but it shows an exceedingly high diffusion barrier, which makes it fail as a SIBs anode [53]. Moreover, through DFT we showed that thanks to the high pyridinic-N of 1 3…”

“…Weng et al reported the synthesis of a C/g-C 3 N 4 composite via a simple one-pot synthesis approach, and the composite delivered a capacity of 254 mAh g −1 at 0.1 A g −1 and 160 mAh g −1 at 0.4 A g −1 (see Fig. 20g) [53]. Recently, Chen et al showed that coating the surface of copper metal current collector with a thin film of 2D-C 3 N 4 can improve Na storage by inhibiting unwanted surface interaction with the liquid electrolyte.…”

“…Cha et al showed that CN possesses a high Na adsorption energy, which can foster attraction of Na atoms into its structure for SIBs batteries [ 31 ]. Although Weng et al [ 62 ] proved that C 3 N 4 displays a very high Na-adsorption energy which limits its application for SIBs, the report of Molaei et al on P-doped C 3 N 4 showed that phosphorus doping is an effective way to decrease the high Na adsorption energy and diffusion barrier in C 3 N 4 (Fig. 8 a-d).…”

Toward an Understanding of the Enhanced CO2 Electroreduction in NaCl Electrolyte over CoPc Molecule‐Implanted Graphitic Carbon Nitride Catalyst

“…As shown in Figure 2e, for bulk g‐C 3 N 4 and CoPc, the binding energy of C 1s at 284.6, 286.2, and 288.3 eV can be corresponding to the typical graphitic sp 2 CC, CO, and CNC, respectively. [ 25,34 ] The characteristic peak of carboxyl (OCOH) for C 1s at 288.7 eV emerges in CoPc/g‐C 3 N 4 compared with other two samples, which can be attributed to the mechanochemical interaction between CoPc and g‐C 3 N 4 with adsorbed oxygen and moisture during BM process. [ 35 ] Furthermore, the XPS survey spectra for the samples of CoPc‐BM and g‐C 3 N 4 ‐BM nanosheets were also performed and further confirmed the significantly introduced oxygen species after BM process, as shown in Figure S6 (Supporting Information).…”

“…[ 23 ] More importantly, the g‐C 3 N 4 with abundant pyridinic N sites can create the microelectric field effects on CoPc molecule and lead to a negatively charged surface of catalyst, [ 24 ] and have an ability of Na + adsorption and storage. [ 25 ] In this way, it is expected that the catalyst can equip with an ability for Na + adsorption in seawater, thus can lead to the suppressed HER and accelerate the CO 2 RR process. Therefore, it can be imagined that the selectivity and activity of CO 2 RR on CoPc molecular catalyst in seawater electrolyte can be modulated and improved through coupling g‐C 3 N 4 .…”