Date published: Nov. 4, 2025

Applications 

• Na-ion batteries
• Hard carbon synthesis
• Hard carbon anode material production

Advantages/Benefits 

• Enhanced sodium storage capacity
• Eliminates impurities formed during synthesis
• Eliminates washing steps to remove impurities 

Background

Sodium-ion batteries (SIBs) are emerging as a promising, cost-effective alternative to lithium-ion batteries for large-scale energy storage, leveraging the abundant supply of sodium. Hard carbon materials are critical anode components for SIBs, known for their high reversible capacities and desirable low-potential plateau. However, achieving optimal performance in hard carbon anodes faces significant hurdles, as current synthesis methods often lead to materials with suboptimal electrochemical properties. There is a need for technologies to mitigate these issues. 

Technology Overview

Scientists at Berkeley Lab have developed a scalable controlled synthesis method for producing high-capacity hard carbon anode materials specifically for sodium-ion batteries. The process employs a carbon-based boat, such as graphite, in conjunction with a reducing gas environment comprising a mixture of gases during high-temperature synthesis. This approach effectively reduces the formation of impurities typically associated with conventional methods that use ceramic boats and inert gas atmospheres, thereby yielding hard carbon with significantly enhanced sodium storage capacity. The initial work was tested in half cells showing no capacity decay, over 100 cycles. 

Development Stage

TRL 4 – Component and/or system validation in laboratory environment 

Inventors

Haegyum Kim

Harshita Lohani

Status 

Patent pending

Opportunities

Available for licensing and collaborative research