Twin-graphene as a Promising Anode Material for Na-Ion Rechargeable Batteries

Abstract

In this work, using density functional theory, a twin-graphene-based anode material is investigated for the use in rechargeable ion batteries with sodium as the intercalating ion. The pristine twin-graphene structure yielded two best adsorption sites of its surface where the Na atoms are adsorbed in a layer-wise fashion. We report a theoretical capacitance of 496.2 mAh/g for Na-adsorbed twin-graphene, which is significantly higher than those of many other carbon allotropies. From NEB calculations, a low diffusion barrier in twin-graphene suggests good diffusivity, and with a moderate value of open-circuit voltage, twin-graphene is a good choice for applications as an anode material in Na-ion rechargeable batteries.

Two-Dimensional Pentagraphyne as a High-Performance Anode Material for Li/Na-Ion Rechargeable Batteries

“…The calculated OCV for different concentrations of Li and Na ions lies in the range 0.971−1.562 and 0.818−1.699 V, respectively. The overall average OCV for Li/Na ions is 1.313/1.366 V. Moreover, this average OCV falls in the moderate range, which confirms its potentiality as an anode material when the operating voltage is below 1.5 V. 10 Furthermore, with increasing storage capacity the OCV significantly decreases (Figure 6c). Diffusion Properties of Li/Na Ions Adsorbed on PGyne.…”

“…A maximum number of eight alkali-metal ions (Li/Na) can be accommodated on the PG-yne surface, which results in 687 mAh g −1 theoretical capacitance of the PG-yne anode material, and this value of theoretical capacitance for LIBs/NIBs is reasonably higher compared to other well-known anode materials used for LIBs/ NIBs such as phosphorene (433/433 mAh g −1 ), 57 Mo 2 C (526/132 mAh g −1 ), 58 Ti 3 C 2 (448/352 mAh g −1 ), 59 etc. In addition, our studied material also possesses higher or comparable storage capacity for application in NIBs compared to many popular 2D materials such as graphyne (372 mAh g −1 ), 60 penta-oC36 (496.90 mAh g −1 ), 49 graphene (308 mAh g −1 ), 61 and its S-, P-, F-, and B-doped counterparts having a capacity of 296, 332, 340, and 345 mAh g −1 , respectively, 61 twin-graphene (496.20 mAh g −1 ), 10 SnP 3 (253.31 mAh g −1 ), 62 MoC 2 (446.90 mAh g −1 ), 63 tetragonal C 24 (232.65 mAh g −1 ), 64 siligraphene (696 mAh g −1 ), 2 GaN (625 mAh g −1 ), 65 Y C (564 mAh g −1 ), 66 MoS 2 /Ti 2 CF 2 (438 mAh g −1 ), 67 V 3 C 2 (606.42 mAh g −1 ), 6868 t-SiC 3 (686 mAh g −1 ), 69 SiS 2 (517 mAh g −1 ), 70 V 2 N MXene (463 mAh g −1 ), 71 VS 2 /graphene, 72 and many others. In addition, the high storage capacity indicates the lower stability of the electrode material (Figure 6b) with respect to the single alkali-metal-ions-adsorbed PG-yne system.…”

“…Rechargeable ion batteries are becoming a hot topic in the scientific community during the present decade and an alternative to conventional energy sources for fulfilling the future energy demand arising due to the increase in global population and rapid urbanization. − Lithium-ion batteries (LIBs) have been in the limelight among metal-ion batteries for a long time due to their long-term cyclic stability, portability, smaller size, high electrochemical potential, high energy and power density, high storage capacity, longer life cycle, and manifold applications starting from cellphones to electric automobiles. − However, the limited availability of lithium results in a high cost of fabrication. In addition, the other major limiting factors for LIBs are that they create environmental hazards such as thermal runaway and explosion occurs at the electrode–electrolyte surface due to the formation of dendrites. , To overcome these shortcomings, researchers have prompted their focus on designing or fabricating other ion batteries as a replacement for LIBs. , Sodium has a similar nature to that of lithium, which provoked researchers to perform extensive studies on sodium-ion batteries (NIBs).…”

“…Due to the presence of a flexible chemical nature and orbital hybridization of carbon, various allotropies of carbon have been experimentally synthesized. − Meanwhile, many carbon allotropies have been theoretically predicted to have versatile properties suitable for technological applications. − Among them, many allotropies such as graphene, ,,, graphyne, graphdiyne, pentagraphene, T-carbon, twin-graphene, penta-oC36, etc., have shown their potentiality as an electrode material. Recently our group has reported on a novel carbon-based allotrope, PG-yne, which is dynamically, mechanically, and thermally stable.…”

Rational Design of Two-Dimensional Porous Boron Phosphide as Efficient Cathode Material for Li and Na Ion Batteries: A First-Principles Study

“…Thus, the intercalation capacity of Na is found to be graeter than that of Li. So, the porous BP monolayer possess ultra high Na storage capacity which is quite similar like penta-graphene (1489 mAh/g), 66 bismuthene (2149 mAh/g), 67 blue AsP (1769.6 mAh/g), 68 Ti 2 PX 2 (X = S, Se, Te; 842−1000 mAh/g) and sufficiently larger than commercial graphite cathodes (372 mAh/g), 52 Hf based Mxenes (444 mAh/g), 69 twin graphene (496.2 mAh/g), 70 Sc 2 C (462 mAh/g), 71 GeS (256 mAh/g), 72 VS 2 (466 mAh/g), 22 GeP 3 (648 mAh/g), 73 α 1 -polymorph of 2D boron sheet (383 mAh/g) 74 and transition metal oxides [NiO 2 , CoO 2 , MnO 2 , VO 2 , ScO 2 (from 50 to 617 mAh/ g)]. 47,63−65 Thus, the porous boron phosphide monolayer is suggested to be a promising cathode material for future application in Li and Na ion battery with sufficiently large capacity and relatively lower diffusion energy barrier.…”