High-throughput theoretical exploration of multifunctional planar MBenes: Magnetism, topology, superconductivity, and anode applications

Pursuing new two-dimensional (2D) materials has been a hot topic in materials science, driven by their potential for diverse applications. Recent research has unveiled stable planar hypercoordinate motifs with unconventional geometric arrangements and bonding patterns that facilitate the synthesis of new 2D materials with diverse applications. Among these, yet the design of 2D transition metal systems featuring planar pentacoordinate boron (ppB) is particularly intriguing. Here we address this gap by proposing a novel family of transition metal boride monolayers (MBenes) composed of ppB and heptacoordinate M motifs. The novelty of our MBenes stems from their distinct atomic arrangements and bonding configurations, setting them apart from traditional 2D materials. High-throughput calculations identified 10 stable MBenes (with the stoichiometry of MB, M ​= ​Cr, Fe, Co, Ni, Cu, Mo, Pd, Ag, Pt, Au) with exceptional thermodynamic, dynamic, thermal, and mechanical stabilities attributed to strong B−B covalent bonds and M−B ionic interactions. Notably, five of these MBenes (M ​= ​Ni, Pd, Pt, Ag, Au) hold high promise as topological superconducting materials with superconducting transition temperatures of 2.4–5.2 ​K. This discovery not only enriches the family of topological superconducting materials but also opens new avenues for quantum device development. Meanwhile, FeB monolayer exhibits robust ferromagnetic properties with a high Curie temperature of ∼750 ​K, which is particularly significant for spintronics applications. In addition, NiB and CuB MBenes demonstrate extremely low sodium diffusion barriers (about 30 and 90 ​meV) and high sodium storage capacities (788 and 734 mAh g−1, respectively), making them promising anode materials for sodium-ion batteries (SIBs). This study expands the selection of electrode materials for SIBs and mitigates some existing limitations in battery technology. Overall, these findings underscore the multifunctional potential of MBenes, positioning them as transformative materials for quantum computing, spintronics, and energy storage applications.