Exploring anchoring performance of defective MgO nanotubes for lithium–sulphur batteries: A density functional theory (DFT) study

Abstract

In recent years, lithium–sulphur batteries have received great attention due to their high theoretical specific capacity. In the exploration of improving battery performance, developing suitable anchoring materials is one of the ways to suppress the shuttle effect which is one of the main problems of lithium–sulphur batteries. In this work, we investigated the anchoring ability of MgO nanotubes (MgONT) and defective MgO nanotubes (MgONTv) to lithium polysulphides (LiPSs) by density functional theory (DFT). The defect formation energy, the HOMO and LUMO of the defective MgONT, the energy difference (ΔE), and the adsorption energy were calculated. The optimized structures of LiPSs adsorbed on the MgONT and MgONTv were also obtained. The calculation results show that MgONTv1 has a strong adsorption effect on LiPSs, and its adsorption energy ranges from −1.78 to −4.51 eV. The adsorption of LiPSs narrows the bandgap of MgONTv. In other words, the conductivity of MgONTv is better than the pristine one. Our study demonstrates that MgONTv has more robust adsorption performance for LiPSs, which is an effective addictive material for the cathode of lithium–sulphur batteries. It can provide a theoretical basis for exploring the application of new one‐dimensional anchoring materials in the cathode of lithium–sulphur batteries.

A First-Principles Study on the Anchoring Properties of Defective Single-Walled Carbon Nanotubes for Lithium-Sulfur Batteries

“…The smaller the formation energy is, the easier the vacancy is to be generated. 41 The formation energy is difficult to obtain experimentally but can be calculated by DFT. The formation of carbon defects can be shown in Table I.…”

“…25 greater than the adsorption energy of LiPSs on the materials listed in Table S1. 13,18,[44][45][46][47][48][49] Furthermore, it can be observed that the adsorption energies for short-chain Li 2 S n (n = 1, 2) on DSWNT are comparatively greater than those for long-chain Li 2 S n (n = 6, 8). This finding suggests that the former has a more favorable potential for inhibiting the shuttle effect.…”