Pseudocapacitance-Dominated MnNb₂ O₆ -C Nanofiber Anode for Li-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Manganese niobium oxide (MnNb2O6) is a promising anode material for lithium-ion batteries.
• Its application is limited by low capacity due to poor electronic conductivity and electron transfer.
• Optimizing structure and components can enhance reversible capacity, but the underlying mechanisms are not fully understood.

Purpose of the Study:

• To investigate the effect of nanoparticle size and carbon confinement on the electrochemical performance of MnNb2O6 anodes.
• To clarify the reasons behind capacity improvements in MnNb2O6-based lithium-ion battery anodes.
• To establish a novel strategy for enhancing the capacity of MnNb2O6 and similar intercalation anodes.

Main Methods:

• Fabrication of MnNb2O6-carbon (MnNb2O6-C) nanofibers and MnNb2O6 nanofibers using electrospinning.
• Characterization of nanoparticle size (~15 nm for MnNb2O6-C NFs, 40-100 nm for MnNb2O6 NFs).
• Electrochemical evaluations including capacity testing and cycling performance analysis.

Main Results:

• MnNb2O6 nanofibers showed an activation process followed by capacity degradation.
• MnNb2O6-C nanofibers delivered high reversible capacity and ultra-stable cycling performance.
• Capacity increment is attributed to partial structure rearrangement, primarily an increase in pseudocapacitance.

Conclusions:

• Diminishing MnNb2O6 nanoparticle size and confining them within a carbon matrix significantly boosts pseudocapacitance-dominated capacity.
• This approach offers a new pathway for improving the reversible capacity of MnNb2O6 anodes.
• The findings provide valuable insights for designing high-performance intercalation anodes for lithium-ion batteries.