Transitioning Advanced Ceramic Electrolytes into Manufacturable Solid-State EV Batteries
Large-scale adoption of electric vehicles requires batteries with higher energy density, lower cost, and improved safety compared with state-of-the-art lithium (Li)-ion batteries. Li-ion’s electrolyte is flammable. Replacing today’s volatile liquid electrolytes with a solid-state electrolyte could increase the Li-ion battery’s abuse tolerance, reducing the need for expensive, bulky battery thermal management systems and protective structures. This would improve system-level energy density and lower cost. In addition, some new solid-state electrolytes enable the use of metallic lithium as an anode material, increasing energy density further. But solid-state Li-based batteries likely require a solid Li-conducting material, and thus far only ceramics and glasses have demonstrated adequate conductivities at ambient temperatures. Ceramics and glasses, however, are brittle, and manufacturing suitable materials and assembling batteries in large quantities with these materials has proven costly and difficult.
Project Innovation + Advantages:
This endeavor continues an OPEN 2015 project, focusing on scaling the technology initially developed by the University of Michigan from lab to pilot scale. Zakuro LLC (Zakuro) will develop a solid state battery using lithium lanthanum zirconate (LLZO), which is a ceramic electrolyte that contains no flammable liquid. LLZO is manufactured with a lithium-free anode, which substantially simplifies assembly. Zakuro aims to scale up production of the ceramic electrolyte pellets from a lab-scale batch process to an industry-standard, roll-to-roll process to enable efficient application of the cathode layer on the ceramic electrolyte. (The anode is the negative elctrode, and the cathode is the positive electrode in a battery cell.) Zakuro will demonstrate cells with twice the energy density of Li-ion (1000 watts per liter) and high specific energy (333 watts per kilogram). The cell will be able to retain 80% of its capacity after charging and discharging 500 times at 1C-rate, or the rate at which a battery discharges in an hour.
Overcoming manufacturing challenges could reduce the cost of solid-state batteries and help enable greater deployment for transportation and stationary storage applications.
The new solid electrolyte, LLZO, can serve as an effective, safer alternative to state-of-the-art Li-ion batteries employing liquid electrolytes.
Widespread deployment of electric vehicles could reduce harmful pollutants from vehicles and improve air quality.
This processing approach has the potential to realize manufacturing costs that are equivalent to Li-ion.