Printed Lithium for Next Generation Battery Technologies

Abstract

Next generation lithium ion batteries will need to utilize anode materials that offer higher energy density and faster charging rates compared to graphite anode. However, widespread commercialization of anodes containing more than a few percent of high energy density materials such as silicon and tin has been hindered by issues such as high first cycle inefficiency and poor cycle life. Loss of active lithium from cathode materials due to SEI formation permanently lowers the cell energy density. Pre-lithiation employs an external, sacrificial source of lithium to offset active lithium losses during the first cycle, allowing more efficient use of lithium from the cathode and therefore raising the cell energy density1,2,3.Livent has developed a proprietary approach to pre-lithiation called Printable Lithium Technology (PLT) that incorporates SLMP into a stable printable formulation. Printable Lithium Formulation (PLF) is comprised of SLMP dispersed in a compatible solvent along with other rheology and performance modifiers to create a formulation that is chemically stable and not prone to separation for extended periods of time. The technology is scalable using industry standard equipment to apply the formulation to the surface of a prefabricated anode. Printable Lithium Technology (PLT) is anode and cathode chemistry agnostic4,5,6. PLT can be used in anodes with a range of silicon content, because lithium loading could be accurately controlled based on the applications’ requirements. Lithium loading control is achieved through the print head designed for pattern printing. We will also discuss safety benefits of using our approach.Figure 1a shows the dQ/dV curve of for baseline SiO/Li half-cell compared to a half-cell with PLF treated SiO. Figure 1a shows the absence of solvent reduction peak in the 0.4V – 0.2V range for the cell incorporating PLT, indicating PLF eliminate the irreversible capacity loss. The voltage vs. capacity curve on the right shows that the first cycle efficiency (FCE) has been improved from 69% in the baseline cell to 87% in the cell with PLT incorporated. Initial voltage is lowered from 1.6V to 0.2V in the cell with treated anode.It can be seen in Figure 2 that PLT can be used in a variety of cell chemistries to improve the cell FCE. Figure 1