First Principles Study of Penta-siligraphene as High-Performance Anode Material for Li-Ion Batteries

Penta-SiCN monolayer as a well-balanced performance anode material for Li-ion batteries

Lithium-ion batteries (LIBs) remain irreplaceable for clean energy storage applications. The intrinsic metallic nature of penta-SiCN ensures its promising application in the electrodes of LIBs. Using first-principles calculations, we evaluate the performance of the intrinsic metallic penta-SiCN monolayer as the anode material for LIBs. Penta-SiCN exhibits a low diffusion energy barrier (0.107 eV) for Li atom migration on Si18C18N18, while the diffusion energy barrier for vacancy migration on Li17Si18C18N18 is only 0.006 eV. Additionally, penta-SiCN possesses a high theoretical capacity of 1485.98 mA h g-1, average open-circuit voltage of 0.97 V, and small volume expansion of 1%. Remarkably, penta-SiCN exhibits robust wettability towards the electrolytes (solvent molecules and metal salts) widely used in commercial LIBs, indicating the excellent compatibility in electrode applications. These intriguing theoretical findings make penta-SiCN a high performance anode material for LIBs.

Armchair silicon carbide nanoribbon for potential anode material in lithium-ion batteries (LIBs)

In this work, we have investigated the electrochemical characteristics of armchair silicon carbide nanoribbon (ASiCNR) for its potential deployment as 2D lithium-ion battery anode material. Density functional theory approach is used to calculate the adsorption energy, storage capacity, and open circuit voltage of ASiCNR for LIB. Adsorption of Li atoms introduces the new energy bands which cross the Fermi level; this results in semiconductor to metallic transition of ASiCNR. It indicates the strong interaction of Li atoms towards the ASiCNR. When adsorption of Li atoms increases one by one, the adsorption energy (E[Formula: see text]) per Li atoms increases gradually. When all favourable sites are adsorbed by Li atoms E[Formula: see text] reached its maximum value and it results in maximum storage capacity of 818 mAhg[Formula: see text] and open circuit voltage of 1.15 V. Diffusion barrier of Li atoms for the substrate is 0.42 eV. Our computational results suggest that ASiCNR can be used as an anode material for Li-ion batteries, and it provides the theoretical background for the future study on ASiCNR and other Li storage structures.

Enhancement in photocatalytic water splitting using van der Waals heterostructure materials based on penta-layers

Recently, van der Waals heterostructures (vdWHs) have been used to improve the performance of 2D materials, enabling more applications. By using first-principles calculations, we have studied the electronic and optical properties of vdWHs composed of penta-siligraphene and other penta-layers (p-Si2C4/p-X; X = Si₂N₄, ZnO₂, Ge₂C₄ or SiGeC₄). The stability of the vdWHs is verified by computing their binding energy, vibrational phonon spectra and ab initio molecular dynamics simulations. By assessing the electronic properties, we have found that the p-Si2C4/p-ZnO2, p-Si2C4/p-Ge2C4 and p-Si2C4/p-SiGeC4 vdWHs are semiconductors with an indirect band gap characterized by type-I band alignment. Meanwhile, the p-Si2C4/p-Si2N4 vdWH is a quasi-direct band gap semiconductor characterized by type-II band alignment. Bader charge analysis and charge density of p-Si2C4/p-Si2N4 vdWHs showed that photogenerated electrons move from the p-Si2N4 monolayer to the p-Si2C4 monolayer limiting the recombination of photogenerated charges and improving the photocatalytic efficiency. Furthermore, the p-Si2C4/p-Si2N4 vdWH exhibits suitable band edge positions compared to isolated monolayers suggesting its potential applicability in photocatalytic water splitting. The calculated optical absorption revealed that the p-Si2N4 monolayer exhibits substantial optical absorption in the ultraviolet (UV) range, while the p-Si2C4 monolayer and the p-Si2C4/p-Si2N4 vdWH show outstanding optical absorption on the order of 10⁵ cm^-1 in the visible and UV ranges. More importantly, the p-Si2C4/p-Si2N4 vdWH can greatly improve the optical absorption in these regions, which leads to high-efficiency usage of solar energy. Our study provides a route to design new vdWHs based on pentagonal monolayers, as well as an efficient photocatalyst for photocatalytic water splitting and optical devices.

Opportunities and challenges for 2D heterostructures in battery applications: a computational perspective

With an increasing demand for large-scale energy storage systems, there is a need for novel electrode materials to store energy in batteries efficiently. 2D materials are promising as electrode materials for battery applications. Despite their excellent properties, none of the available single-phase 2D materials offers a combination of properties required for maximizing energy density, power density, and cycle life. This article discusses how stacking distinct 2D materials into a 2D heterostructure may open up new possibilities for battery electrodes, combining favourable characteristics and overcoming the drawbacks of constituent 2D layers. Computational studies are crucial to advancing this field rapidly with first-principles simulations of various 2D heterostructures forming the basis for such investigations that offer insights into processes that are hard to determine otherwise. We present a perspective on the current methodology, along with a review of the known 2D heterostructures as anodes and their potential for Li and Na-ion battery applications. 2D heterostructures showcase excellent tunability with different compositions. However, each of them has distinct properties, with its own set of challenges and opportunities for application in batteries. We highlight the current status and prospects to stimulate research into designing new 2D heterostructures for battery applications.

Strain- and electric field-enhanced optical properties of the penta-siligraphene monolayer

The effect of biaxial strain and an external electric field on the optical properties of the penta-siligraphene monolayer are reported.

Emerging properties of carbon based 2D material beyond graphene

Graphene turns out to be the pioneering material for setting up boulevard to a new zoo of recently proposed carbon based novel two dimensional (2D) analogues. It is evident that their electronic, optical and other related properties are utterly different from that of graphene because of the distinct intriguing morphology. For instance, the revolutionary emergence of Dirac cones in graphene is particularly hard to find in most of the other 2D materials. As a consequence the crystal symmetries indeed act as a major role for predicting electronic band structure. Since tight binding calculations have become an indispensable tool in electronic band structure calculation, we indicate the implication of such method in graphene's allotropes beyond hexagonal symmetry. It is to be noted that some of these graphene allotropes successfully overcome the inherent drawback of the zero band gap nature of graphene. As a result, these 2D nanomaterials exhibit great potential in a broad spectrum of applications, viz nanoelectronics, nanooptics, gas sensors, gas storages, catalysis, and other specific applications. The miniaturization of high performance graphene allotrope based gas sensors to microscopic or even nanosized range has also been critically discussed. In addition, various optical properties like the dielectric functions, optical conductivity, electron energy loss spectra reveal that these systems can be used in opto-electronic devices. Nonetheless, the honeycomb lattice of graphene is not superconducting. However, it is proposed that the tetragonal form of graphene can be intruded to form new hybrid 2D materials to achieve novel superconducting device at attainable conditions. These dynamic experimental prospects demand further functionalization of these systems to enhance the efficiency and the field of multifunctionality. This topical review aims to highlight the latest advances in carbon based 2D materials beyond graphene from the basic theoretical as well as future application perspectives.

Penta-BCN monolayer with high specific capacity and mobility as a compelling anode material for rechargeable batteries

With the increasing demand for sustainable and clean energies, seeking high-capacity density electrode materials applied in rechargeable metal-ion batteries is urgent. In this work, using first-principles calculations, we evaluate the ternary pentagonal BCN monolayer as a compelling anode material for metal ion batteries. Calculations show that the penta-BCN monolayer has favorable metallic behaviors after adsorbing Li (Na) atoms. More interestingly, the saturated adsorption systems provide a large storage capacity of 2183.12 (1455.41) mA h g^-1 for Li (Na) ions. A low energy barrier of 0.14 (0.16) eV for Li (Na) diffusion is observed, being smaller than the reported other two-dimensional anode materials. Also, the wrinkled structure of penta-BCN has been demonstrated to be very beneficial to improve the energy density and cycle life of batteries. The calculated low open-circuit voltage and peculiar surface area expansion together with the thermal stability of saturated intercalation structures, further indicate that the penta-BCN monolayer has great potential as the anode material for Li (Na) ion batteries.

Layered silicon carbide: a novel anode material for lithium ion batteries

The structural stability of carbon and the high theoretical capacity of silicon was the motivation for investigating the prospects of layered silicon carbide (SiC).

Density Functional Theory Investigation of Mixed Transition Metals in Olivine and Tavorite Cathode Materials for Li-Ion Batteries

Lithium-ion batteries (LIBs) are widely used in various electronic devices and have garnered a huge amount of attention. In addition, evaluation of the intrinsic properties of LIB cathode materials is of considerable interest for practical applications. Therefore, through first-principles calculations based on the density functional theory, we investigated the structural, electronic, electrochemical, and kinetic properties of mixed transition metals, that is, Ni-substituted LiMnPO₄ (LMP) and LiMnPO₄F (LMPF) cathode materials, that is, LiMn_0.5Ni_0.5PO₄ (LMNP) and LiMn_0.5Ni_0.5PO₄F (LMNPF), respectively, which have not been extensively studied. We also evaluated their delithiated phases, that is, Mn_0.5Ni_0.5PO₄ (MNP) and Mn_0.5Ni_0.5PO₄F (MNPF). Our calculations suggest that Ni substitution significantly affected the structural and electrochemical properties. After Li insertion, the MNPF unit-cell volume increased by about 8%, lower than that of pristine MnPO₄F. The Li intercalation voltage also increased in LMNP (4.27 V) and LMNPF (5.23 V). In addition, the migration barrier was calculated to be 0.4 eV for LMNPF, lower than that of LMPF. This study may provide insights for developing LMNP and LMNPF cathode materials in LIB applications.