Theoretical Exploration of Single-Layer Tl₂O as a Catalyst in Lithium–Oxygen Battery Cathodes

Abstract

Two-dimensional transition-metal oxides have been widely explored as catalysts in high-capacity nonaqueous lithium–oxygen batteries due to their excellent electrochemical performance in the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), but little attention has been paid to non-transition-metal oxides. Here, we employ density functional methods based on the Perdew–Burke–Ernzerhof (PBE) functional with dispersion correction and the Heyd–Scuseria–Ernzerhof hybrid functional (HSE06) to investigate the mechanisms of the nucleation and decomposition processes of Li4O2(s), i.e., discharge and charge processes on single-layer Tl2O (SL-Tl2O) in lithium–oxygen batteries. HSE06 with the spin–orbital coupling effect is adopted to calculate the band gap of SL-Tl2O. It is demonstrated that the spin–orbital coupling effect is significant in predictions of not only electronic but also thermodynamic properties for heavy-element compounds such as Tl2O. The formation of LiO2(s) is initiated by the adsorption of oxygen molecules instead of lithium atoms on the surface. The intermediate reaction products strongly interact with SL-Tl2O, which causes an overpotential of 1.47 V during the electrochemical reaction. The electronic conductivity analysis of lithium oxides adsorbed on SL-Tl2O demonstrates that the electronic conductance of the layer does not change during the ORR/OER. The adsorption enthalpies of five frequently used nonaqueous solvents (tetrahydrofuran, 1,2-dimethoxyethane, 1,3-dioxolane, dimethyl carbonate, and propiolic acid) on SL-Tl2O indicate that SL-Tl2O is stable in the electrolytes. All of these calculated results indicate that SL-Tl2O is a feasible catalyst for the ORR/OER in nonaqueous lithium–oxygen batteries.

Toward Large-Capacity and High-Stability Lithium Storages via Constructing Quinone–2D-MnO2-Pillared Structures

“…We also calculated the surface energy of 2D-MnO 2 from where E s is the surface energy, E 2D is the calculated energy of the pristine 2D-MnO 2, E bulk is the energy of the bulk β-MnO 2 crystal, A is the surface area in the selected supercell, and N is the number of MnO 2 molecules in the slab supercell. The calculated surface energy is 0.41 J·m –2 , which is slightly higher than that of the pristine 2D-Tl 2 O . Three distinct quinone–2D-MnO 2 -pillared structures were constructed and then optimized for further investigations.…”

“…The battery reactions of LIBs can be denoted as where the Gibbs free energy changes of this reaction can be determined by where Δ E is the total energy changes of the reaction, p is the pressure of the system, Δ V is the solid volume change, and Δ S is the entropy changes of the reaction. In eq , the terms p Δ V and T Δ S could be neglected in the calculations since their influence on Gibbs energy changes are quite small. , Thus, eq can be approximately described by where E Li, x i is the total energy of the pillared structures in lithium concentration x i and E Li is the total energy of lithium atom calculated from the bcc structures. The relationship between open-circuit voltages and Gibbs energy changes is given by where U is the open-circuit voltage and n e is the number of transferred electrons during the battery reaction.…”

Aprotic lithium air batteries with oxygen-selective membranes

“…Mostly, the research on aprotic lithium air battery was conducted using pure oxygen [69][70][71][72][73][74][75][76][77][78][79]. The use of pure oxygen in practical application had some serious issues like additional storage weight, refilling of cylinder and safety issues which are considered to be the hindrances in practical LAB.…”

How Do Oxygen Vacancies Influence the Catalytic Performance of Two‐Dimensional Nb2O5 in Lithium‐ and Sodium‐Oxygen Batteries?

“…Various types of catalysts were adopted to ameliorate the electrochemical performance of the cells including pure metals (Pt, Co, Ir, and Ru), [11–14] but their high price restricts them in practical applications. Compared with pure metals, metal oxides [15,16] stand out due to their exceptional stability and performances, especially two‐dimensional metal oxides (TMOs) [17,18] for their abundant surface area for reaction and adjustable electronic properties. 2D‐Nb 2 O 5 , also known as T‐Nb 2 O 5 , is considered to be a promising material for fast lithium‐ion energy storage due to its unique intercalation pseudocapacitance [19,20] .…”