Manipulation of the MoO₂/MoSe₂ Heterointerface Boosting High Rate and Durability for Sodium/Potassium Storage

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Sodium/potassium ion storage faces challenges with larger ion sizes and slow kinetics.
• Developing suitable host materials is crucial for efficient ion accommodation and transport.

Purpose of the Study:

• To construct a novel MoO2/MoSe2 heterostructure embedded in N,P-doped carbon nanofibers (MoO2/MoSe2@NPC).
• To enhance rate performance and cycle life for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs).

Main Methods:

• Selenation of polyoxometalate within electrospinning fibers.
• In situ local phase transformation to form MoSe2 nanosheets within MoO2.
• Controlled preparation temperature to optimize heterointerfaces.
• Density Functional Theory (DFT) calculations to analyze ion/electron transfer.

Main Results:

• The 1D MoO2/MoSe2@NPC structure facilitates ion diffusion and provides abundant active sites.
• Optimized heterointerfaces between MoO2 and MoSe2 exhibit synergistic effects.
• DFT confirmed an internal electric field enhancing ion/electron kinetics.
• SIBs: 382 mAh g-1 at 0.1 A g-1 (200 cycles), 266 mAh g-1 at 2 A g-1 (2000 cycles).
• PIBs: 216 mAh g-1 at 200 cycles, 125 mAh g-1 at 1 A g-1 (2000 cycles).

Conclusions:

• The developed MoO2/MoSe2@NPC material demonstrates superior performance for SIBs and PIBs.
• Interface engineering is a promising strategy for designing advanced anode materials.
• This approach boosts fast Na+/K+ storage kinetics for next-generation batteries.