Regulating Sodium Deposition through Gradiently-Graphitized Framework for Dendrite-Free Na Metal Anode.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium metal anodes (NMA) are promising for low-cost sodium metal batteries.
• Anode/separator interface issues, like sodium dendrites, limit NMA safety and battery life.

Purpose of the Study:

• To develop a Na deposition-regulating strategy for NMAs.
• To enhance the safety and cycle life of sodium metal batteries.

Main Methods:

• Designed a gradiently graphitized 3D carbon fiber (CF) framework host (grad-CF).
• Investigated Na deposition behavior within the grad-CF host.
• Tested Na@grad-CF anodes in full cells with a Na3V2(PO4)3 (NVP) cathode.

Main Results:

• Na deposition was guided to the bottom of the anode, away from the separator.
• The grad-CF host enabled stable NMA cycling at 6 mA cm⁻².
• Full cells demonstrated a reversible capacity of 73 mAh g⁻¹ after 500 cycles with 0.13% decay.

Conclusions:

• The grad-CF host effectively suppresses dendrite formation in NMAs.
• This strategy significantly improves the safety and long-term stability of sodium metal batteries.