Realizing a 3 C Fast-Charging Practical Sodium Pouch Cell

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-ion batteries (SIBs) are promising for fast charging due to Na+ properties.
• Practical SIBs are limited to 1C charging due to metallic sodium plating on hard carbon anodes.
• Overcoming sodium plating is key to achieving high-rate capabilities in energy-dense SIB pouch cells.

Purpose of the Study:

• To develop an ampere-hour-level sodium-ion pouch cell capable of 3C charging.
• To investigate phosphorus-sulfur interphase chemistry for enhanced sodium-ion interface kinetics.
• To enable fast charging in energy-dense SIBs without detrimental metallic sodium plating.

Main Methods:

• Rational electrolyte regulation to form Na3PO4 and Na2SO4 in the solid-electrolyte interphase (SEI).
• Utilizing phosphorus (P)-sulfur (S) interphase chemistry to modify SEI properties.
• Fabricating and testing O3-Na(Ni1/3Fe1/3Mn1/3)O2||HC and Na3V2(PO4)3||HC pouch cells.

Main Results:

• Achieved 3C charging in an energy-dense (126 Wh/kg) O3-Na(Ni1/3Fe1/3Mn1/3)O2||HC pouch cell without sodium plating.
• Demonstrated excellent capacity retention of 91.5% over 200 cycles at 3C.
• A power-type Na3V2(PO4)3||HC pouch cell exhibited an impressive 50C fast-charging capability.

Conclusions:

• Phosphorus-sulfur interphase chemistry effectively lowers the Na+ desolvation energy barrier and enhances interfacial kinetics.
• The developed SIBs overcome the limitations of sodium plating, enabling significantly faster charging rates.
• This approach provides a viable strategy for developing high-performance, fast-charging sodium-ion batteries.