Confining CoSe/MoSe₂ Heterostructures in Interconnected Carbon Polyhedrons for Superior Potassium Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Metal selenides are promising anode materials for potassium-ion batteries (PIBs).
• Challenges include poor potassium storage kinetics and significant volume expansion during cycling.
• Heterostructure engineering combined with structural design offers a strategy to overcome these limitations.

Purpose of the Study:

• To construct a novel CoSe/MoSe2 heterojunction encapsulated in nitrogen-doped carbon polyhedron and interconnected by 3D nitrogen-doped carbon nanofibers (CoMoSe@NCP/NCFs).
• To enhance potassium ion storage kinetics and structural stability in PIBs.
• To demonstrate a viable approach for superior PIB anode development.

Main Methods:

• Ingenious construction of CoSe/MoSe2 heterojunction within a nitrogen-doped carbon polyhedron framework.
• Interconnection of the structure using 3D nitrogen-doped carbon nanofibers.
• Electrochemical characterization to evaluate performance in PIBs.

Main Results:

• The CoMoSe@NCP/NCFs composite exhibits abundant heterointerfaces with built-in electric fields.
• The unique carbon structure provides efficient electron/ion transfer pathways and mechanical buffering.
• Outstanding cycle life with 206 mAh g⁻¹ retained after 2500 cycles at 2 A g⁻¹.
• Decent rate performance with 161 mAh g⁻¹ achieved at 10 A g⁻¹.

Conclusions:

• The developed CoMoSe@NCP/NCFs composite effectively addresses the kinetic and stability issues in PIB anodes.
• The synergistic effect of heterojunctions and the carbon framework promotes rapid and stable potassium storage.
• This research presents a viable strategy for designing high-performance anode materials for potassium-ion batteries.