  This study comprehensively examined the structural, electronic,
electrochemical, and energy storage properties of boron-vacancy induced porous
boron nitride monolayers (BN:VB) as multifunctional materials, anodes for MIBs
and H2 storage applications. Our computational approaches, density functional
theory (DFT), ab initio molecular dynamics (AIMD), and thermodynamic analysis,
revealed exceptionally high energy and gravimetric densities for MIBs and H2
storage, respectively. We investigated the interactions of Li, Na, and K atoms
on BN:VB, which strongly bonded with binding energies stronger than their bulk
cohesive energies, which ensured structural stability and the absence of metal
clustering. Electronic properties, analyzed through spin-polarized partial
density of states (PDOS), band structure, and Bader charge analysis, revealed
significant charge transfers from the metal atoms to BN:VB, enhancing the
electronic conductivity of the latter. Theoretical specific capacities were
calculated as 1821.53, 786.11, and 490.51 mA h/g for Li, Na, and K,
respectively, which comfortably exceeded the conventional anodes, such as
graphite. Average open-circuit voltages (OCVs) were found as 0.15, 0.25, and
0.32 V, for Li, Na, and K, respectively, indicating strong electrochemical
stability. Diffusion studies showed lower barriers of 0.47, 0.08, and 0.60 eV
for Li, Na, and K, respectively, with increased metal loadings, suggesting
enhanced mobilities and charge/discharge rates. On the other side, the
metal-functionalized BN:VB monolayers exhibited remarkably high H2 gravimetric
capacities, supported by Langmuir adsorption model-based statistical
thermodynamic analysis. Average adsorption energies of H2 on 4Li-, 4Na-, and
4K@BN:VB, were found in perfect range for practical storage applications.
