Improved ion adsorption capacities and diffusion dynamics in surface anchored MoS 2 ⊥Mo 4/3 B 2 and MoS 2 ⊥Mo 4/3 B 2 O 2 heterostructures as anodes for alkaline metal-ion batteries.

First-principles calculations were performed to analyze the atomic structures and electrochemical energy storage properties of novel MoS 2 ⊥boridene heterostructures by anchoring MoS 2 nanoflakes on Mo 4/3 B 2 and Mo 4/3 B 2 O 2 monolayers. Both thermodynamic and thermal stabilities of each heterostructure were thoroughly evaluated from the obtained binding energies and through first-principles molecular dynamics simulations at room temperature, confirming the high formability of the heterostructures. The electrochemical properties of MoS 2 ⊥Mo 4/3 B 2 and MoS 2 ⊥Mo 4/3 B 2 O 2 heterostructures were investigated for their potential use as anodes for alkaline metal ion batteries (Li + , Na + and K + ). It was revealed that Li + and Na + can form multiple stable full adsorption layers on both heterostructures, while K + forms only a single full adsorption layer. The presence of a negative electron cloud (NEC) contributes to the stabilization of a multi-layer adsorption mechanism. For all investigated alkaline metal ions, the predicted ion diffusion dynamics are relatively sluggish for the adsorbates in the first full adsorption layer on MoS 2 ⊥boridene heterostructures due the relatively large migration energies (>0.50 eV), compared to those of second or third full adsorption layers (<0.30 eV). MoS 2 ⊥Mo 4/3 B 2 O 2 exhibited higher onset and mean open circuit voltages as anodes for alkaline metal-ion batteries than MoS 2 ⊥Mo 4/3 B 2 hybrids because of enhanced interactions between the adsorbate and the Mo 4/3 B 2 O 2 monolayer with the presence of O-terminations. Tailoring the size and horizontal spacing between two neighboring MoS 2 nano-flakes in heterostructures led to high theoretical capacities for LIBs (531 mA h g -1 ), SIBs (300 mA h g -1 ) and PIBs (131 mA h g -1 ) in the current study.