Abstract:
Various transition metal dichalcogenides materials have been investigated from bulk to monolayer phases for different advanced technological applications. Tin disulfide monolayer offers advantages as an anode material for Li/Na-ion batteries, although it cannot be considered an ideal for direct exploitation. We systematically performed a comparative study of the adsorption and diffusion behaviour of Li/Na on a pristine SnS2 monolayer and on a SnS2 monolayer with a S-vacancy for enhancement of electrochemical performance, using the density functional theory approach. Although all the adsorption sites are exothermic, it was established that Li/Na adatoms mostly prefer to bind strongly on a SnS2 monolayer with a S-vacancy but avoiding the S-vacancy site. It was established that avoiding the S-vacancy site along the path, an excellent diffusion barriers of 0.19 eV for Li and 0.13 eV for Na were achieved, suggesting possible ultrafast charge/discharge rate. Due to reduced molar mass, the SnS2 monolayer with a S-vacancy has a slightly higher storage capacity than its pristine counterparts for both Li and Na adatoms. The obtained open circuit voltage values are within the range of 0.25–3.00 V assuring that the formation of dendrites can surely be averted for the envisaged battery operation. Understanding the effects of an S-vacancy on the electrochemical properties of Li/Na on the SnS2 monolayer allows us to consider possible improvements to energy storage devices that can be applied as a result of improved anode material.
