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The Seebeck effect in graphene with uniform Kekulé lattice distortion has been studied using the tight-binding model combined with the nonequilibrium Green's function method. The numerical results of this work show that the Seebeck coefficient of the O-shaped Kekulé graphene can be enhanced by modulating the gate voltage. At room temperature (T ≈ 300 K), the Seebeck coefficient for the armchair nanoribbon is S c ≈ 1370 μV/K and for the zigzag nanoribbon is S c ≈ 1260 μV/K. At low temperature (T ≈ 128 K), the Seebeck coefficient for the armchair nanoribbon is S c ≈ 2500 μV/K. In addition, the nano-structuration of the O-shaped Kekulé graphene layer induces an anisotropic behavior in the Seebeck effect. Our work provides an idea for the fabrication of efficient and controllable thermoelectric effect devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Recent advances on alkali-metal ion batteries are reviewed for CrB 4 and MoB 4 monolayer. • Metal-ion adsorption, diffusion, storage capacity and charge/discharge are discussed. • Metallicity remains well maintained throughout the adsorption process. • Excellent stability during lithiation, sodiation, and potassiation, demonstrating its potential for practical applications in advanced battery systems. Finding high-storage-capacity anode materials has been a focus of ion-battery research. Two-dimensional (2D) materials have shown promise as high-performance electrode-materials as they have developed gradually. Here we examined the viability of 2D CrB 4 and MoB 4 monolayers as optimal anode-materials for Li/Na/K ion batteries using first-principles DFT calculations. Preliminary investigations showed that both materials exhibited thermodynamic, structural, and mechanical stability. We found that a strongly negative adsorption energy can help in stabilizing the adsorption of metal-ions on materials surface instead of clustering, that ensures metal-ion-batteries stability. The maximum theoretical storage capacities of Li, Na, and K ions adsorbed on the CrB 4 monolayer surface were 1689,1126 and 750 mA h g−1, respectively, while those on the surface of MoB 4 were 1155,770 and 513 mA h g−1, respectively. Additionally, calculated open-circuit voltages for Li-ions (0.84,0.82 V), Na-ions (0.25,0.32 V), and K-ions (0.85,0.81 V) for CrB 4 and MoB 4 monolayers, respectively. Electronic properties showed that increasing the metal ions concentration enhanced both materials' electrical conductivity and remained the metallic in nature after adsorption. However, Li/Na/K energy barriers are nevertheless consistent with various typical 2D anode materials. The light shaded on 2D MoB 4 and CrB 4 is anticipated to identify new anode materials for LIBs, NIBs, and KIBs. [ABSTRACT FROM AUTHOR]

As a rapidly evolving 2D monolayer material, tungsten tetraboride MBene exhibits innate advantages in electrochemical applications because of its unique graphene-like structure and metallic properties. In this study, we utilized first-principles calculations to identify the potential applications of WB 4 as an anode material in rechargeable alkali-metal-ion batteries. The findings imply that the Li, Na, and K adsorption on the WB 4 surface results in exceptionally high conductivity, and the WB 4 monolayer can effectively adsorb these ions with significant adsorption energies of −2.516 eV, −2.356 eV, and −2.941 eV for Li, Na, and K ions, respectively. The results indicate that WB 4 exhibits excellent stability during lithiation, sodiation, and potassiation. Notably, we propose high storage capacities for LIBs (708mAh/g), SIBs (472mAh/g), and KIBs (177 mAh/g), with maintained structural stability for the adsorption of these metal ions. The measured average open circuit voltages for WB 4 were found to be 0.77 V (Li), 0.73 V (Na), and 0.80 V (K), and metallicity remain good maintained within the entire adsorption process. The calculated migration energy barriers for Li, Na, and K were 0.47 eV,0.21 eV and 0.13 eV respectively. The notable properties of WB 4 make it an advantageous electrode material for alkali-metal ion batteries. [Display omitted] • This research investigates recent advancements in alkali-metal ion batteries, focusing on WB 4. • Key aspects such as metal-ion adsorption, diffusion, storage capacity, and charge/discharge processes are examined. • The material upholds its metallicity consistently throughout the adsorption stages. • WB 4 showed remarkable stability during lithiation, sodiation, and potassiation, highlighting its significant potential for practical use in advanced battery systems. [ABSTRACT FROM AUTHOR]