Heterostructure Coupling Yolk-Shelled Nanosphere for CoSe/C@NC@MoSe₂/N,P-C Toward Efficient Sodium/Potassium Storage

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Developing high-performance anode materials is crucial for advancing sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs).
• Existing anode materials often face challenges with structural stability and ion diffusion limitations during cycling.

Purpose of the Study:

• To engineer a novel yolk-shelled structure, CoSe/C@NC@MoSe2/N,P-C (CMSC), for enhanced electrochemical performance in SIBs and PIBs.
• To investigate the synergistic effects of heterostructure and architecture design on ion storage capabilities.

Main Methods:

• Fabrication of a yolk-shelled CMSC structure featuring a CoSe core within a carbon matrix and double shells of N-doped carbon and MoSe2 in N,P-doped carbon.
• Electrochemical characterization of CMSC as an anode material in SIBs and PIBs, including cycling stability and rate performance tests.
• Assembly and testing of full cells using CMSC anodes paired with specific cathode materials.

Main Results:

• The CMSC anode demonstrated excellent cycling stability, retaining 262.3 mAh g-1 after 5000 cycles at 20.0 A g-1 for SIBs.
• For PIBs, a stable capacity of 171.3 mAh g-1 was achieved over 500 cycles at 5.0 A g-1.
• Full cells exhibited high energy densities, with CMSC//Na3V2(PO4)3 reaching 263.9 Wh kg-1 at 215.5 W kg-1.

Conclusions:

• The designed yolk-shelled CMSC structure effectively accommodates mechanical stress and shortens ion diffusion paths.
• The heterostructure between CoSe and MoSe2 contributes to improved reaction kinetics and cycling stability.
• CMSC presents a promising anode material for practical applications in high-performance SIBs and PIBs.