Yolk-Double-Shell ZnPS₃/NC@C Polyhedra Engineered via Kirkendall-Effect-Driven Etching for Superior Sodium Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Transition metal phosphosulfides (TMPs) show promise for sodium-ion batteries (SIBs) due to their layered structures.
• Key challenges for TMPs in SIBs include poor electronic conductivity and structural instability during cycling.
• Developing robust anode materials is crucial for advancing SIB technology.

Purpose of the Study:

• To engineer a stable and conductive anode material based on zinc phosphosulfide (ZnPS3) for SIBs.
• To address the intrinsic limitations of poor conductivity and structural degradation in ZnPS3.
• To establish a generalizable strategy for designing advanced electrode materials through morphological control and composite engineering.

Main Methods:

• Fabrication of yolk-double-shell ZnPS3/N-doped carbon@carbon (ZnPS3/NC@C) polyhedra using a Kirkendall-effect-mediated strategy.
• Utilized tannic acid (TA) etching and a resorcinol-formaldehyde (RF) coated ZIF-8 precursor.
• Characterization of the material's structure, morphology, and electrochemical performance in SIBs.

Main Results:

• The ZnPS3/NC@C anode demonstrated a unique yolk-double-shell architecture with an integrated conductive network.
• Achieved high reversible capacities of 925.7 mAh g⁻¹ (charge) and 1128.9 mAh g⁻¹ (discharge) at 0.1 A g⁻¹.
• Exhibited excellent long-term cyclability, retaining 96.9% of capacity over 2000 cycles at 2.0 A g⁻¹.

Conclusions:

• The rationally designed yolk-double-shell architecture effectively enhances electronic conductivity and accommodates volume expansion.
• The ZnPS3/NC@C anode offers superior sodium storage performance compared to bare ZnPS3 materials.
• This work presents a versatile design approach for developing high-performance anode materials for next-generation batteries.