The electric vehicle market’s biggest hurdles today are improving and cost reducing battery technology. A new fabrication technique could allow solid-state automotive lithium-ion batteries to adopt nonflammable ceramic electrolytes using the same production processes as in batteries made with conventional liquid electrolytes. These conventional Li-ion manufacturing tools are driving better fabrication options to enable battery makers to produce lighter, safer, and more energy-dense batteries.
The melt-infiltration technology developed by materials science researchers at the Georgia Institute of Technology uses electrolyte materials that can be infiltrated into porous yet densely packed, thermally stable electrodes.
The one-step process produces high-density composites based on pressure-less, capillary-driven infiltration of a molten solid electrolyte into porous bodies, including multilayered electrode-separator stacks.
«While the melting point of traditional solid state electrolytes can range from 700 degrees Celsius to over 1,000 degrees Celsius, we operate at a much lower temperature range, depending on the electrolyte composition, roughly from 200 to 300 degrees Celsius,» explained Gleb Yushin, a professor in the School of Materials Science and Engineering at Georgia Tech. «At these lower temperatures, fabrication is much faster and easier. Materials at low temperatures don’t react. The standard electrode assemblies, including the polymer binder or glue, can be stable in these conditions.»
The new technique, to be reported March 8 in the journal Nature Materials, could allow large automotive Li-ion batteries to be made safer with 100% solid-state nonflammable ceramic rather than liquid electrolytes using the same manufacturing processes of conventional liquid electrolyte battery production. The patent-pending manufacturing technology mimics low-cost fabrication of commercial Li-ion cells with liquid electrolytes, but instead uses solid state electrolytes with low melting points that are melted and infiltrated into dense electrodes. As a result, high-quality multi-layered cells of any size or shape could be rapidly manufactured at scale using proven tools and processes developed and optimized over the last 30 years for Li-ion.
«Melt-infiltration technology is the key advance. The cycle life and stability of Li-ion batteries depend strongly on the operating conditions, particularly temperature,» Georgia Tech graduate student Yiran Xiao explained. «If batteries are overheated for a prolonged period, they commonly begin to degrade prematurely, and overheated batteries may catch on fire. That has prompted nearly all electric vehicles (EV) to include sophisticated and rather expensive cooling systems.» In contrast, solid-state batteries may only require heaters, which are significantly less expensive than cooling systems.
Story Source: Materials provided by Georgia Institute of Technology. Note: Content may be edited for style and length.