Comparison between Sodium or Potassium-Ion Batteries and Lithium-Ion Counterparts for Energy-Saving: A Physico-Chemical Study by Density Functional Theory

Abstract

As the incremental deficiency of Li resources, it is significant and instant to supersede Li with other earth-abundant elements for electrochemical energy storage devices. While lithium-ion batteries (LIBs) have their difficulties, the demand to improve beyond-lithium batteries goes beyond the issues of sustainability and safety. Accordingly, Na/K-atom energy storage devices, including rechargeable batteries and ionic capacitors with similar energy storage mechanisms to Li-ion devices, have attracted widespread concerns due to the abundant reserves of Na/K and low cost. Therefore, in this article, it has been evaluated the promising alternative alkali metals of sodium-ion and potassium-ion, batteries. A comprehensive investigation on hydrogen grabbing by Li₂[SnO–SiO], Na₂[SnO–SiO] or K₂[SnO–SiO] was carried out including using DFT computations at the “CAM–B3LYP–D3/6-311+G (d,p)” level of theory. The hypothesis of the hydrogen adsorption phenomenon was confirmed by density distributions of CDD, TDOS, and ELF for nanoclusters of Li₂[SnO–SiO]–2H₂, Na₂[SnO–SiO]–2H₂ or K₂[SnO–SiO]–2H₂. The fluctuation in charge density values demonstrates that the electronic densities were mainly located in the boundary of adsorbate/adsorbent atoms during the adsorption status. As the advantages of lithium, sodium or potassium over Sn/ Si possess its higher electron and hole motion, allowing lithium, sodium or potassium instruments to operate at higher frequencies than Sn/Si instruments. Among these, sodium-ion batteries seem to show the most promise in terms of initial capacity.