New binder/solvent system from Argonne, FMC facilitates use of stabilized Li metal powder in Li-ion electrodes; lower cost, higher energy density
As part of a four-year DOE-funded project, researchers at the US Department of Energy’s Argonne National Laboratory, working with FMC Corporation, have developed a novel polymer binder and solvent system facilitating the use of FMC’s unique Stabilized Lithium Metal Powder (SLMP) as a performance-enhancing additive in Li-ion battery electrodes.
SLMP-based materials can enable commercialization of batteries with simplified formation process, lower irreversible capacity losses (leading to higher energy densities) and allow for a wider range of cathode materials—e.g., non-lithium-providing materials—to be utilized for transportation applications. Argonne has patents pending on the polymer binder and solvent technologies, as well as a new activation method.
Members of the Argonne team, with colleagues from Lawrence Berkeley National Laboratory, report in a new paper in the Journal of Power Sources on the positive performance impact of applying SLMP in a graphite anode as a prelithiation method. Among the findings were:
First cycle capacity loss of SLMP prelithiated cell was largely reduced and the corresponding first cycle Coulombic efficiency was significantly improved.
The graphite/NMC cell with SLMP prelithiation but without any standard cell formation process showed better cycle performance than that of none SLMP containing cell with standard formation process.
Prelithiation of graphite electrode with SLMP promoted stable solid electrolyte interface (SEI) formation on the surface of graphite anode.
Manufacturing cost for cell formation can be significantly reduced with additional of SLMP.
This new prelithiation method also implies that the promising future of application of SLMP in other higher energy density anodes such as Si and Sn, which are currently unlikely used in commercial lithium-ion batteries because of the large first cycle irreversible capacity loss.—Wang et al. (2014)
Non-stabilized lithium powder is unstable when exposed to air, and needs to be handled in an argon-filled glove box. FMC’s SLMP particles—with a metallic lithium content of at least 98%—are coated with a protective layer to stabilize the lithium. As a result, the stabilized lithium is safe to handle in the dry room environment, and can be transported by air or sea (non- pyrophoric by DOT test).
However, SLMP is not compatible with conventional binder and solvent slurry materials. The novel polymer binder and solvent system, developed by a team led by Argonne chemist John Zhang, demonstrated excellent compatibility with SLMP, thus enabling SLMP for slurry processing.
The innovative new polymer binder/solvent system allows the SLMP to be evenly distributed in the electrode, enabling optimum use of each lithium particle in the SLMP material. Argonne researchers also developed new methods to activate the SLMP. Compression of the electrode laminates is typically employed to activate SLMP particles. The battery manufacturing cost can be greatly reduced due to the simplified SLMP activation method developed by Argonne.
SLMP enables the use of new anode materials with both large reversible and irreversible capacities, FMC notes, such as silicon and tin composites. Further, the cathode choice would no longer be limited to lithium-providing materials—i.e., a much wider selections of non-lithium-providing materials that are more overcharge tolerant, lower in cost, and with larger capacities are enabled, such as FeF3, BiF3, and MnO2.
SLMP-derived ultra-thin lithium metal anodes could also be beneficial to the development of beyond lithium-ion systems due to the surface coatings that might reduce reactivity and porous topology that might mitigate dendrite growth and thus improve safety.
FMC recently awarded Zhang and his colleagues—Khalil Amine, Shengwen Yuan, Zheng Xue and Jung-Je Woo—its Scientific Achievement Award for their significant research and development efforts.
This project is part of the Integrated Laboratories and Industry Research Program, which is supported by the Energy Department’s Office of Energy Efficiency and Renewable Energy.
Zhihui Wang, Yanbao Fu, Zhengcheng Zhang, Shengwen Yuan, Khalil Amine, Vincent Battaglia, Gao Liu (2014) “Application of Stabilized Lithium Metal Powder (SLMP) in graphite anode – A high efficient prelithiation method for lithium-ion batteries,” Journal of Power Sources, Volume 260, Pages 57-61 doi: 10.1016/j.jpowsour.2014.02.112
Yangxing Li, Brian Fitch (2011) “Effective enhancement of lithium-ion battery performance using SLMP,” Electrochemistry Communications, Volume 13, Issue 7, Pages 664-667 doi: 10.1016/j.elecom.2011.04.003