What question did this study set out to answer?

The aim is to enhance the stability and performance of Na-ion batteries at high temperatures using AlF3 coating.

January 16, 2026Advanced Science0 citationsOpen Access

AlF 3 Mediated In‐Situ Cathode Interface Stabilization Enables High‐Rate and Long‐Life Na‐Ion Batteries at Elevated Temperature

YYYameng YinChina Three Gorges University QLQinxia LiuChina Three Gorges University ZZZhiyuan ZhangChina Three Gorges University

Key Points

The aim is to enhance the stability and performance of Na-ion batteries at high temperatures using AlF3 coating.
Introduced AlF3 coating on Na3V2(PO4)2O2F cathodes
Characterized the properties of the coated cathodes
Evaluated cycling stability at 55°C
Assessed performance at various charge rates (10 C and 5 C)
Achieved 84.9% capacity retention after 1000 cycles at 10 C
Observed 96.8% capacity retention at 5 C
Confirmed formation of a robust inorganic-rich cathode electrolyte interface
Enhanced ionic conductivity due to F─Al─O bridging bonds facilitating electron transfer.

Abstract

ABSTRACT The instability of the cathode electrolyte interface (CEI) under high voltage and elevated temperature poses a major challenge to the practical application of Na 3 V 2 (PO 4 ) 2 O 2 F (NVOPF) cathodes in sodium‐ion batteries (SIBs). To overcome this issue, we introduce a dual‐functional AlF 3 coating that effectively stabilizes the interface while improving bulk electronic conductivity. The AlF 3 ‐modified NVOPF@C exhibits exceptional cycling stability at 55°C, maintaining 84.9% capacity after 1000 cycles at 10 C in half cells and 96.8% at 5 C in full cells using hard carbon anodes. Detailed characterization reveals that the AlF 3 coating promotes the formation of a robust, inorganic‐rich CEI, primarily composed of a NaF/AlF 3 /NaAlF 4 ternary fluoride composite. This newly constructed CEI layer not only acts as a protective barrier to suppress detrimental interfacial side reactions but also serves as an efficient ionic conductor to facilitate Na + diffusion. In addition, the AlF 3 coating induces the creation of F─Al─O bridging bonds with surface oxygen groups, which collaborate with carbon nanotubes to establish a highly continuous conductive network that enables efficient electron transfer. These findings underscore the crucial significance of constructing a stable inorganic‐dominated CEI and continuous conductive pathways for developing high‐rate and thermally stable SIBs.

问 AI

Bookmark

View Full Paper