Novel Architecture for Dendrite Free Li-ion Batteries

University of Pittsburgh scientists have developed a novel electrode to produce dendrite-free, high-efficiency lithium-ion batteries (LIBs) together with a fabrication method to produce these electrodes. Using electrospun carbon nanofibers (CNF), a polydimethylsiloxane (PDMS) layer on copper foil can produce an electrode (CNF-PDMS/Cu) suitable for stabilization of lithium metal plating for subsequent use in LIBs. This novel CNF-PDMS/Cu architecture has a high columbic efficiency (CE) and is stable over hundreds of cycles. These novel electrodes could produce dendrite-free Li-metal anodes and lead to the development of high-performance, low-cost LIBs revolutionizing the LIB market.

A novel design and production method of electrodes for use in LIBs coating commercially available copper foil with PDMS polymer and electrospun CNF. The PDMS prevents the formation of dendrites on the Cu foil. This novel anode has a high CE (>99%) and a high specific capacity, and could result in the development of high-capacity LIBs. 

Description

LIBs are used in many consumer goods including electric vehicles, laptops, and medical devices with demand for these batteries growing. The global market for LIBs could exceed $400bn in the next five years to match consumer need for portable power. A major roadblock in meeting the growing demand for LIBs is low CE and the formation of lithium dendrites on the electrodes during plating (i.e., deposition of Li on the anode surface), leading to battery failure and safety risks, including fires. This novel approach aims to improve the capacity of LIBs through increasing CE and reducing the impacts of lithium plating on capacity or safety of the LIB. Using a copper foil and Li-impervious polymer (PDMS), dendrite-free Li-metal anodes can be produced with high specific capacity (>2000 mAh/g) and CE (>99.2%).

Applications

• Lithium-ion battery development
• Consumer electronics
• Electric vehicles

Advantages

Current attempts to use Cu foil anodes have led to failure within 30–50 cycles and exhibit low CE (<90%) rendering them unsuitable for LIBs. In this novel architecture, electrospun CNF are used as the contact material for Li-metal plating. These CNF are bound to the electron rich Cu foil using PDMS. This design has several advantages. Firstly, PDMS prevents Li plating on the Cu foil preventing dendrite formation and is key to the improved performance of these electrodes compared to existing technology. Secondly, the CNF is almost inactive to intercalation from the Li ions, stabilizing the plating of the CNF. These novel electrodes could lead to development of cost-effective novel sulfur cathodes, reducing the cost of LIBs while improving the efficacy and life cycle.

Invention Readiness

CNF-PDMS/Cu architecture was produced. Laboratory testing demonstrated possible specific capacity of 3000mAh/g, based on CNF weight and a CE of up to 99.85% with minimal fluctuations, even over 600 cycles, confirming stable Li plating occurs.

IP Status

https://patents.google.com/patent/WO2021091934A1