Heterointerfacial and Architectural Engineering in MOF‐Templated Corn‐Like FePS3‐ZnPS3‐C@NC Anode for Durable Sodium Storage

Why It Matters

The breakthrough tackles conductivity and stability limits of transition‑metal thiophosphite anodes, advancing high‑energy, long‑life sodium‑ion batteries.

Key Takeaways

• MOF‑on‑MOF templating yields corn‑like heterostructure
• N‑doped carbon coating buffers mechanical strain
• FePS3/ZnPS3 interface creates built‑in electric field
• 1294 mAh g⁻¹ initial capacity, 87.6 % after 1200 cycles
• DFT confirms enhanced Na⁺ adsorption and charge transfer

Pulse Analysis

Sodium‑ion batteries (SIBs) have emerged as a cost‑effective alternative to lithium‑ion systems, yet their commercial adoption is hampered by anode materials that struggle with low electronic conductivity and drastic volume changes during cycling. Transition‑metal thiophosphites (MPS₃), such as FePS₃, offer high theoretical capacities but suffer from these exact drawbacks, limiting rate performance and lifespan. Researchers therefore seek strategies that simultaneously boost charge transport and preserve structural integrity, a dual challenge that has motivated the recent exploration of heterostructured and architecturally engineered anodes.

The new study employs a MOF‑on‑MOF templating route to fabricate a corn‑like FePS₃‑ZnPS₃ heterostructure, subsequently encapsulated in a conformal N‑doped carbon (NC) layer. This design creates a built‑in electric field at the FePS₃/ZnPS₃ interface, as confirmed by density‑functional theory, which lowers Na⁺ adsorption energy and accelerates interfacial charge transfer. The elastic NC coating acts as a flexible matrix that accommodates expansion, while the heterojunction supplies rapid electron pathways. Together, these features enable swift ion diffusion and mitigate mechanical degradation.

Electrochemical testing demonstrates an initial discharge capacity of 1 294.5 mAh g⁻¹ at 0.1 A g⁻¹ and a retention of 87.6 % after 1 200 cycles at 2 A g⁻¹, outperforming most reported MPS₃‑based anodes. Such durability and rate capability bring SIBs closer to meeting the energy‑density and cycle‑life requirements of grid‑scale storage and electric‑vehicle applications. Moreover, the MOF‑templated synthesis is compatible with scalable production, suggesting a viable pathway for commercializing high‑performance sodium anodes. Future work may extend this heterointerfacial concept to other transition‑metal chalcogenides, further broadening the materials toolbox for next‑generation batteries.