APPLICATIONS OF TECHNOLOGY:
- Lithium ion batteries for electric vehicles, hybrids and consumer electronics
- High specific capacity anodes with good cycling performance and electronic contact
- Scalable electrochemical fabrication; silicon wafers can be reused
A Berkeley Lab research team has developed a technology to fabricate nanoporous silicon networks using a scalable electrochemical process. These networks, which have controllable porosity and thickness, can be released from reusable silicon wafers and transferred to flexible, conductive substrates, where they serve as high performance lithium ion battery electrodes demonstrating good electronic contact between network and current collector.
This technology addresses the issues of limited specific charge storage capacity, low energy density, low power density, and limited life span that have hampered silicon’s use as an electrode material. The researchers’ silicon network anodes with 80% porosity had high specific capacity – 2,570 mAh/g initially and above 1,000 mAh/g after 200 cycles, with no electrolyte additives. An oxide coating identified by the researchers may improve performance.
Silicon has attracted intense interest as an electrode material due to its high theoretical charge capacity. But it has drawbacks, undergoing dramatic structural and volume changes during lithium ion insertion and extraction. While various silicon nanostructures such as nanowires, nanotubes, and carbon / silicon spheres have been produced, the goal of low cost and fast throughput along with mass and morphology control has remained elusive. Berkeley Lab’s nanoporous silicon networks are specifically intended to solve this problem and serve as a promising, higher capacity alternative to existing graphite anodes in lithium ion batteries.
DEVELOPMENT STAGE: Proven principle
STATUS: Patent pending. Available for licensing or collaborative research.
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SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:
REFERENCE NUMBER: 2013-182