Despite the promise of sodium-ion batteries (SIBs) for large-scale energy storage, the development of high-performance anode materials remains a critical challenge. Here, we report that the two-dimensional β-phase carbon selenide (β-CSe) monolayer exhibits remarkable Na-ion storage properties identified through comprehensive first-principles calculations. The buckled honeycomb structure demonstrates exceptional stability with positive phonon frequencies and preserved C-Se bonds during molecular dynamics at both room temperature (300 K) and elevated temperature (400 K). Na adsorption occurs preferentially at hollow sites with strong binding energies (−2.95 eV on C-side) and substantial charge transfer (0.82|e|), thermodynamically favoring uniform Na distribution which may help suppress dendrite formation. Strikingly, the material exhibits ultrafacile Na diffusion with maximum energy barriers of only 0.019-0.021 eV, among the lowest reported for SIB anodes, suggesting exceptional rate performance. Basin-hopping Monte Carlo simulations reveal a theoretical capacity of 589 mAh/g with an average insertion potential of 1.11 V, while the material advantageously transitions from semiconductor to metallic behavior upon Na insertion. The anisotropic Poisson's ratio (as low as 0.05) further minimizes volume changes during cycling. These findings establish β-CSe as a promising candidate for high-performance SIB anodes and provide valuable insights for designing advanced battery materials.

This study investigates the electronic and superconducting properties of Ni₃AC (A: Mg, Zn, and Cd) antiperovskites through first-principles computational methods. Importantly, Ni₃MgC has been identified as a superconductor with a transition temperature (T_c) of 8.644 K, while Ni₃ZnC and Ni₃CdC exhibit T_c values of 2.172 K and 3.861 K, respectively, in remarkable agreement with experimental. The electron–phonon interaction strength in these materials suggests medium-coupling superconductivity. This study provides significant insights into the mechanisms driving superconductivity in metal-carbide antiperovskites, identifying opportunities for their use in advanced technologies.

Photocatalytic water splitting represents a promising approach for sustainable hydrogen production, with two-dimensional Janus materials offering unique advantages through intrinsic electric fields that enhance charge separation. We present a comprehensive first-principles investigation of Janus AlXY₂ (X = Ga, In; Y = S, Se, Te) monolayers using density functional theory and ab initio molecular dynamics simulations. All six systems exhibit excellent structural, thermal, and mechanical stability with HSE06 bandgaps of 2.029–2.969 eV suitable for UV-light absorption. The asymmetric structure generates strong intrinsic electric fields of 5.391–6.437 V perpendicular to the monolayer plane, significantly enhancing photogenerated charge carrier separation. While pristine monolayers show poor hydrogen evolution reaction (HER) activity with Gibbs free energies of 1.937–2.371 eV, strategic introduction of metal vacancies dramatically improves performance, reducing ΔG_H values to −0.371 to ＋0.607 eV and approaching optimal catalytic conditions. These findings demonstrate the potential of defect-engineered 2D Janus AlXY₂ materials for efficient photocatalytic hydrogen production.