TiC MXene High Energy Density Cathode for Lithium–Air Battery

MXenes are reported to be great supercapacitor and lithium-ion battery material recently. In this article, the density functional theory (DFT) calculations show that using TiC MXene Ti_nC_{n− 1}O₂ (n = 2, 3, 4) as the cathode of lithium–air batteries (LABs) can potentially improve its efficiency by increasing the cathode conductivity and lowering the charging overpotential. In addition, the conservative predicted storage density is as high as ≈0.5 kWh kg⁻¹. Compared with the bulk TiC{111}, the favorable structural agreement between the TiC MXenes and Li₂O₂, and better interfacial conduction help Li₂O₂ continuously grow on the TiC MXene; and the higher specific surface area (SSA) makes more Li₂O₂ deposition possible. The predicted reaction path calculations reveal that TiC MXenes have the charging overpotential of 0.13 V because they are excellent catalysts in the oxygen evolution reaction (OER). Thus, the lower charging overpotential can extremely suppress the side reactions and accelerate the OER rate. All the evidence supports that TiC MXene is a potential high energy density cathode for LABs.