N-Doped Porous Carbon Encapsulated MnFe₂O₄ Nanoparticles as Advanced Anodes for Li-Ion Batteries

Transition metal oxide MnFe₂O₄ is considered a promising anode material for Li-ion batteries owing to its high theoretical specific capacity. However, this material has two bottleneck problems, i.e., poor conductivity and serious volume expansion during cycling. In this work, MnFe₂O₄ nanoparticles were successfully encapsulated in the matrix of N-doped porous carbon via a sol–gel method. As a result, the N-doped carbon matrix enhances the electronic conductivity of the composites. The special porous structure increases the contact area between the electrode material and the electrolyte and facilitates the rapid infiltration of the electrolyte. At a calcination temperature of 400 °C, the MnFe₂O₄/C composite shows a high initial discharge specific capacity of 1207.0 mAh g⁻¹ at 0.2 A g⁻¹ and retains a reversible specific capacity of 1100.1 mAh g⁻¹ after 200 cycles. The simple design of metal oxide nanomaterials encapsulated in N-doped porous carbon provides a new direction for improving the electrochemical performance of electrode materials for Li-ion batteries.

A brief abstract: MnFe₂O₄ nanoparticles were successfully encapsulated in the matrix of N-doped porous carbon via a sol–gel method. At a calcination temperature of 400 °C, the MnFe₂O₄/C composite shows a high initial discharge specific capacity of 1207.0 mAh g⁻¹ at 0.2 C and retains a reversible specific capacity of 1100.1 mAh g⁻¹ after 200 cycles.