Inducing Mn defects within MnTiO₃ cathode for aqueous zinc-ion batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Layered manganese-based materials are promising cathodes for aqueous zinc-ion batteries (AZIBs) due to their low cost, non-toxicity, and safety.
• However, poor electrical/ionic conductivity in these materials leads to sluggish reaction kinetics, limiting their performance.

Purpose of the Study:

• To introduce MnTiO3 as a new cathode material for AZIBs.
• To investigate the effect of in-situ induced manganese defects on the electrochemical performance of MnTiO3.
• To understand the mechanism of defect-enhanced kinetics through theoretical calculations.

Main Methods:

• Synthesis and characterization of MnTiO3 as a cathode material.
• Electrochemical testing of MnTiO3 in AZIBs, including cycling stability and rate capability.
• Density Functional Theory (DFT) calculations to analyze the electronic structure and ion interaction at defect sites.

Main Results:

• MnTiO3 exhibits enhanced reaction kinetics and improved cycling stability upon the in-situ formation of manganese defects during the first charge.
• DFT calculations confirm uniform charge distribution at defect sites, promoting attraction of H+ and Zn2+ ions.
• The Mn-defect MnTiO3 cathode achieved a capacity of 233.8 mAh/g at 100 mA/g and retained 115 mAh/g at 400 mA/g after 450 cycles.

Conclusions:

• In-situ induced manganese defects in MnTiO3 are a viable strategy to overcome kinetic limitations in layered cathode materials for AZIBs.
• This work offers a new avenue for developing high-performance cathode materials and understanding their mechanisms in AZIBs.