Highly Stable Two-Dimensional Iron Monocarbide with Planar Hypercoordinate Moiety and Superior Li-Ion Storage Performance

Abstract

We report on the theoretical discovery of Iron monocarbide binary sheets stabilized at two-dimensional confined space, which we call tetragonal-FeC (t-FeC) and orthorhombic-FeC (o-FeC), respectively. From the energy viewpoint, the proposed t-FeC is the global minimum configuration in the 2D space, and each carbon atom is four-coordinated with ambient four Iron atoms. Strikingly, the o-FeC monolayer is an orthorhombic phase with planar pentacoordinate carbon moiety and planar seven-coordinate Fe moiety. To our knowledge, this monolayer is the first example of a simultaneously pentacoordinate carbon and planar seven-coordinate Fe-containing material. State-of-the-art theoretical calculations confirm that all these monolayers have significantly dynamic, mechanical, and thermal stabilities. Among these two monolayers, t-FeC monolayer shows a higher theoretical capacity (395 mAh g -1 ), and can stably adsorb Li up to t-FeCLi 3 . Low migration energy barrier is predicted as small as 0.26 eV for Li, which result in the fast diffusion of Li atom on this monolayer. Moreover, electron-phonon calculations coupled with Bardeen-Cooper-Schrieffer arguments suggest t-FeC can be potential two-dimensional superconductors with 6.77 K superconducting transition temperature.

Crystal Structure Prediction Approach to Explore the Iron Carbide Phases: Novel Crystal Structures and Unexpected Magnetic Properties

“…Meanwhile, the energy is much lower than γ′-FeC and the lowest-enthalpy structure reported in database, − which consists of a triangular iron sublattice and triangular prism interstitial carbon atoms. In fact, such a structural feature of FeC­( Pnnm ) also appeared in two-dimensional iron monocarbide (orthorhombic-FeC) . In the new region (0.5 < y / x < 1), we found a new type of iron sublattice in the novel phases of Fe 7 C 5 ( I 2), Fe 4 C 3 ( Cmcm ), Fe 5 C 4 ( C 2/ m ), Fe 6 C 5 ( Imm 2), and Fe 7 C 6 ( P 6 3 / m ), as shown in Figure .…”

Ultimate Resourcization of Waste: Crab Shell-Derived Biochar for Antimony Removal and Sequential Utilization as an Anode for a Li-Ion Battery

“…Furthermore, the highly dispersed antimony buffers the volume expansion in the alloying process of antimony and Li . Other components in the material are also useful in LIBs, including carbon, iron oxide, and rare-earth-doped materials . Based on the abovementioned implications, we designed a scheme to convert the antimony-enriched waste adsorbent into an anode material for a Li-ion battery.…”

A graphene-like semiconducting BC2P monolayer as a promising material for a Li-ion battery and CO2 adsorbent

“…Moreover, we added the parameter IVDW = 10 corresponding to the DFT-D2 method of the Grimme van der Waals (vdW) correction to consider the weak vdW interaction between the adsorbed materials and the substrate. 21,25,26,31 To confirm that BC 2 P monolayer is a promising material for anode material and CO 2 adsorbent, potential adsorption sites and the adsorption energy ( E ad ) of one Li atom or one CO 2 molecule on the 4 × 2 × 1 supercell of BC 2 P monolayer have to be investigated. Thus, the adsorption energy of the Li atom or CO 2 molecule on the supercell of the BC 2 P monolayer was calculated by 27 E ad = ( E sub-Li n − E sub − nE Li )/ n or E ad = ( E sub-CO 2 − E sub − E CO 2 )/ n where E Li , E CO 2 , E sub , E sub-Li n and E sub-CO 2 are the total energy of a single Li atom, a CO 2 molecule, the supercell of BC 2 P monolayer (namely substrate), the supercell with n Li atoms or a CO 2 molecule, respectively.…”

“…[15][16][17][18][19][20][21][22][23][24][25] Except for experimental efforts, theoretical prediction also plays an important role in acquiring new 2D materials for the applications of LIBs and CO 2 molecule capture. In terms of LIBs, some metal borides and carbides have been predicted and studied, such as Mo 2 B 2 , 17 Ti 2 B 2 , 18 Zr 2 B 2 , 19 TaC 2 , 20 MC 6 (M = Cu, Ag, Au), 21 V 2 C 2 , 22 ScC 2 , 23 MoC, 24 NiC 3 , 25 FeC, 26 and BiC monolayer. 27 In addition, there are predicted 2D materials for the LIBs using nonmetal elements, such as C 2 Si, 28 C 3 N, 29 CP 3 , 30 and B 7 P 2 monolayer.…”