Super-sodiophilic seeds for dendrite‑free sodium metal batteries

Background

As the demand for renewable energy sources and electric vehicles grows, there is a pressing need for efficient, sustainable, and cost-effective battery tech­nologies. Sodium-metal batteries (SMBs) show great promise for energy storage applications due to the natural abundance and low cost of sodium compared to lithium. However, SMBs are limited by non-uniform deposition of sodium metal at the anode called dendrites. Dendrites are needle-like struc­tures that can pierce the battery’s separator and cause short circuits, posing safety risks and reducing the battery’s lifespan. Existing approaches to miti­gate dendrite growth have not been entirely successful, often resulting in high overpotentials, low Coulombic efficiency, and limited cycle life. Addressing these issues is crucial for advancing SMB technology and unlocking its potential for widespread use in next-generation energy storage solutions.

Technology overview

This technology addresses non-uniform sodium deposition and uncontrollable dendrite growth by implementing super-sodiophilic BiF₃ seeds in current collectors. The efficacy of this technology was demonstrated by incorporating BiF₃ into a matrix of carbon nanotubes (CNTs). Na@CNT-BiF₃ symmetrical cells achieved an extremely low overpotential (13.5mV) and superior cycle life (2,000+ hours).

During battery charge, sodium metal infiltrates the CNT matrix within seconds, facilitating uniform sodium deposition along the current collector. In addition to CNTs, super-sodiophilic BiF₃ was successfully coated on a Cu current collector, yielding a high Coulombic efficiency of 99%. The low overpotential, long cycle life, and high Coulombic efficiency indicate minimal energy loss and high performance. Furthermore, Na-S pouch cells (N/P ratio of 2, E/S of 4μL mg⁻¹) achieve a capacity of 661mAh/g after 50 cycles, demonstrating this technology’s promise in a practical battery configuration. The ability to maintain enhanced stability during extended cycling highlights this tech­nology’s potential as a practical, cost-effective anode for next-generation energy storage solutions.

Benefits

• Super-sodiophilic BiF₃ enhances battery lifespan (2,000+ hours in symmetrical cells) and safety by preventing dendrite formation.
• BiF₃ seeds can be applied to various current collectors, offering versatility in battery design and optimization.
• BiF₃ seeds allow Na-S pouch cells to achieve a high capacity (661mAh/g), while operating at low N/P ratio (2) and E/S (4μL mg⁻¹), demonstrating its potential in energy-dense, cost-effective batteries.

Applications

• Sodium-ion battery manufacturing
• All-solid-state battery (ASSB) manufacturing
• Electric vehicle manufacturing

Opportunity

• This technology addresses key challenges in SMBs, preventing dendrite formation and offering enhanced anode stability.
• This highly tunable method improves sodium battery performance and safety with low-cost materials.
• This technology is available for exclusive licensing, presenting a unique opportunity to seamlessly integrate sodiophilic BiF₃ seeds into battery manufacturing processes.

Publication

Long-life sodium‑sulfur batteries enabled by super-sodiophilic seeds (DOI: 10.1039/D4EE02996H)