Laser Processing of Solid-State Lithium Batteries

Project Overview

Solid-state lithium batteries (SSLBs) have received intensive interest as a next-generation energy-storage solution. The fabrication of oxide-based SSLBs requires sintering of the ceramic electrolytes. However, conventional furnace sintering method for the tape-casted ceramic electrolyte component results in poor densification, Li loss, and surface contamination. Those problems result in low ionic conductivity, high surface-charge resistance, and dendrite growth issues that lead to failure of solid-state batteries. In this project, we developed advanced processing techniques based on laser sintering, which has multiple advantages such as direct energy absorption, ultrafast heating/cooling rates, highly tunable laser-heating parameters, good integration, and scaling capabilities. We used FTIR and in situ characterization techniques (synchrotron x-ray radiography/tomography and high-speed imaging) to understand laser–battery material interactions. Densification kinetics and particle size effects were revealed using phase field modeling in parallel with furnace sintering and in situ ultrasmall angle x-ray scattering characterization. Our work shows that laser sintering with localized heating and fast processing time can mitigate Li loss and accelerate densification. Thin (< 100 micrometers), dense (> 95%), clean, and crack-free Ta-doped Li7La3Zr2O12 films were successfully achieved. The unique anisotropic deformation behavior with 3D interface makes this method outstanding compared with other reported sintering methods. Reactive laser sintering with further reduced material and processing cost were also demonstrated with one-step densification and grain-orientation tuning capabilities. Furthermore, laser co-sintering with much shorter treatment time resulted in fewer thermal-induced reactions between solid-state electrolyte and cathode in contrast to conventional furnace sintering. The developed bundle solutions of laser techniques accelerate the integration of solid-state batteries to achieve their expected high performance.

Mission Impact

The technology developed in this project enables NNSA to create new capabilities for energy security and climate resilience. Solid-state batteries with high energy density and safety advantages are the future choice of power sources for electric vehicles. Our laser sintering approach, with demonstrated advantages and uniqueness in the fabrication of SSE films and integration of SSE with cathode components, addresses the manufacturing challenges of SSLBs. The project supported talent hiring to LLNL, including two postdocs and one SES2 technician. The project also strengthened LLNL-university collaborations through subcontract, which supported one graduate student.

Publications, Presentations, and Patents

Hammons, J., et al., 2022. "Pore and Grain Chemistry During Sintering of Garnet-Type Li6.4La3Zr1.4Ta0.6O12 Solid-State Electrolytes." Journal of Materials Chemistry A 10: 9080-9090 2022.

Ramos, E., et al. 2022. "CO2 Laser Sintering of Garnet-Type Solid-State Electrolytes." ACS Energy Letters 7: 3392-3400 2022.

Ye, Jianchao, et al. 2022. "Additive Manufacturing of Solid State Batteries." Solid-State Battery Summit. Chicago, IL. Aug. 8-9 . 2022.

Wood, Marissa, et al. 2022. "Co-Sintered Solid Electrolyte/Cathode Interfaces in Solid-State Batteries." Materials Research Society Spring Meeting 2022, Honolulu, HI. May 8-13, 2022.

Ramos, E., et al. 2022. "CO2 Laser Sintering of Garnet-Type Li-ion Conductors." Materials Research Society Spring Meeting 2022, Honolulu, HI. May 8-13 2022.

Ye, Jianchao, et al. 2022. "Interactions Between Laser and Solid-State Lithium Battery Materials." Materials Research Society Spring Meeting 2022, Honolulu, HI. May 8-13 2022.