Lithium ceramic for batteries can be synthesized at low temperatures without the need for sintering.
A lithium ceramic could act as a solid electrolyte in a more powerful and cost-efficient generation of rechargeable lithium-ion batteries. The challenge is to find a production method that works without sintering at high temperatures. In a paper recently published in the journal Angewandte Chemie, a research team has introduced a sinter-free method for the efficient, low-temperature synthesis of these ceramics in a conductive crystalline form.
The Evolution of Electric Vehicle Batteries
Two factors dominate the development of batteries for electric vehicles: power, which determines the vehicle range; and cost, which is critical in the competition with internal combustion engines. The US Department of Energy aims to accelerate the transition from gasoline-powered vehicles to electric vehicles and has set ambitious goals for reducing production costs and increasing the energy density of batteries by 2030. These targets cannot be achieved with conventional lithium-ion batteries.
The Promise of Solid-State Batteries
A highly promising approach to making smaller, lighter, significantly more powerful, and safer batteries is to use solid-state cells with anodes made of metallic lithium instead of graphite. In contrast to conventional lithium-ion batteries, which have liquid organic electrolytes and use a polymer film to separate the anodic and cathodic compartments, all components of a solid-state battery are solids.
A thin ceramic layer simultaneously functions as a solid electrolyte and separator. It is very effective against both the dangerous short circuits caused by the growth of lithium dendrites and thermal runaway. In addition, they contain no easily inflammable liquids.
Challenges with Ceramic Electrolytes
A suitable ceramic electrolyte/separator for cells with high energy density is the garnet-type lithium oxide Li7La3Zr2O12−d (LLZO). This material must be sintered together with the cathode at over 1050 °C to convert the LLZO to the rapid lithium-conducting cubic crystalline phase, sufficiently densify it, and strongly bind it to the electrode. However, temperatures above 600 °C destabilize sustainable low-cobalt or cobalt-free cathode materials while also driving up production costs and energy consumption. New production methods that are more economical and sustainable are needed.
A Revolutionary Synthetic Process
A team led by Jennifer L. M. Rupp at
Reference: “Time-Temperature-Transformation (TTT) Diagram of Battery-Grade Li-Garnet Electrolytes for Low-Temperature Sustainable Synthesis” by Yuntong Zhu, Michael Chon, Carl V. Thompson and Jennifer L. M. Rupp, 18 September 2023, Angewandte Chemie International Edition.
DOI: 10.1002/anie.202304581
The study was funded by the National Science Foundation.