MnTiO₃ as a carbon-free cathode for rechargeable Li–O₂ batteries

Li-O2 batteries (LOBs) are next-generation energy storage systems. However, their main challenges are the sluggish kinetics of oxygen reduction and evolution reactions (ORR/OER) and high charge overpotentials due to the formation of discharge product (Li2O2). To address this challenge, developing a catalyst with a unique structure and exceptional catalytic properties is crucial to enhancing the reversible cycling performance of LOBs, particularly under high current density conditions. Herein, the transition metal-based perovskite MnTiO3 was examined as a carbon-free cathode catalyst using density functional theory (DFT) calculations and experimental techniques. The intrinsic advantages of MnTiO3 stem from the coexistence of Mn and Ti energy levels near the Fermi level, as revealed by our density of states (DOS) analysis. This electronic structure facilitates ORR/OER, thus endowing MnTiO3 with a bifunctional role in promoting battery performance. Our DFT-based investigation elucidates the surface stability and catalytic properties of MnTiO3. Furthermore, Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) confirm that the electrochemical reaction on MnTiO3 follows a two-electron pathway. Our findings reveal that a LOB with MnTiO3 exhibits a total overpotential of 1.18 V and 1.55 V using DFT and electrochemical measurements, respectively. High current densities up to 1 A g−1 also highlight its potential as a cathode catalyst for LOBs.

DDC Class

540: Chemistry

621.3: Electrical Engineering, Electronic Engineering

660: Chemistry; Chemical Engineering

Publication version

publishedVersion

Lizenz

https://creativecommons.org/licenses/by/3.0/

Name

d4ta05571c.pdf

Type

Main Article

Size

3.25 MB

Format

Adobe PDF

Options

MnTiO₃ as a carbon-free cathode for rechargeable Li–O₂ batteries