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Lasers Improve Fabrication of Solid-State Batteries
Lawrence Livermore scientists have devised a method for fabricating all-solid-state lithium metal batteries—a promising choice for the safe, high-energy-density power sources that are greatly needed for electrical devices, vehicles, and energy grid storage. The team determined that laser sintering (i.e., compacting and coalescing a solid material by heat or pressure, without liquefaction) solid-state electrolyte films with carbon dioxide overcomes difficulties in manufacturing solid-state batteries.
The laser sintering technique yields scalable, low-cost, high-energy-density solid-state lithium batteries for advanced energy storage across national security missions. These laser-based techniques also can be applied to other fields, such as additive manufacturing of polymers, ceramics, and metals.
Typical lithium-ion batteries use organic liquid electrolytes and graphite anodes, which lead to safety hazards and lower the energy density—problems that are addressed by solid-state lithium-metal batteries. “This work provides a unique, scalable, and widely applicable ultrarapid laser sintering technique to overcome the difficulties associated with classic methods for integrating solid-state electrolytes for practical solid-state lithium-metal battery applications,” says Livermore materials scientist and project lead Jianchao Ye, a coauthor of the cover article on the technique featured in the October 14, 2022, ACS Energy Letters.
Unlike current technologies, the new sintering approach has three critical advantages: it is ultrafast, mitigates lithium loss, and yields anisotropic shrinkage, which greatly reduces film thickness. Also, a point-scanning strategy produces wave-like surface topology, enabling 3D interfacial contacts with electrode materials. “Together with unprecedented microstructural controllability, laser sintering provides new opportunities to realize the promise of superionic conductors in solid-state battery applications,” says Ye.
Contact: Jianchao Ye (925) 423-6696 (ye3@llnl.gov).
Laser “Twist” Offers Insights into Plasma Physics
Andrew Longman, a postdoctoral fellow with Lawrence Livermore’s High Energy Density Science Center, proposed that spiral phase mirrors will enable scientists to “twist” laser light and generate an optical vortex. An optical vortex is a “spinning” beam with a helical wavefront. Electromagnetic vortices occur naturally throughout the universe. Scientists have sought methods to investigate in a laboratory how strong electromagnetic vortices interact with matter, specifically plasma. The use of high-intensity lasers to generate electromagnetic vortices has the potential to unlock new physics when such beams interact with the freely moving ions and electrons of plasma, as shown in Longman’s recent paper on these effects, published in the August 2023 edition of Physics of Plasmas.
Longman proposed using spiral mirrors in high-power laser systems to “twist” the laser light and create powerful magnetic fields. He improved the fabrication process of his spiral mirror design using Lawrence Livermore’s unique optic fabrication capabilities with magnetorheological finishing (MRF) technology for polishing precise corrective topographical structures onto optical surfaces. Longman used optical vortices to rotate plasma to extremely high angular speeds. To generate vortices at ultrahigh intensities, Longman used an off-axis spiral phase mirror with a spiral only as deep as a wavelength (less than 0.001 millimeters) imprinted on its surface. The laser beam twists when it reflects off the mirror, transferring this angular momentum to any kind of target—solid, gas, or plasma—allowing researchers to drive helical plasma waves and currents capable of generating very strong magnetic fields, as well as trapping, guiding, and accelerating particles to enhance laser‒plasma interactions. The mirror design has been extremely successful, generating the highest intensity optical vortices ever produced.
Contact: Andrew Longman (925) 423-5682 (longman1@llnl.gov).
Soil Viruses Respond Rapidly to Environmental Changes
Lawrence Livermore and University of California (UC) scientists have found that grassland viral communities exhibit robust, but highly dynamic, spatial structuring on the scale of just a single field. “Knowing the composition and turnover of viral communities across space and time is necessary to determine what constrains host–virus interactions in soil,” says project co-lead Jennifer Pett-Ridge. “We found that the soil ‘virosphere’ is highly diverse, active, and spatially structured, capable of rapid responses to changing environmental conditions, particularly the amount of rainfall.”
Soils are physically, chemically, and biologically heterogeneous. The intricate network of aggregates and pore spaces in the soil sustains a varying range of properties and restricts the movement of microorganisms. Viruses have countless effects on host metabolism, evolution, and Earth’s biogeochemical cycles. The abundance of soil viruses hints at their likely importance in terrestrial ecosystems. A rainfall manipulation experiment in the new study showed that reduced precipitation can reshape soil viral community composition. Recent observations suggest that water availability is a major driver of soil viral community assembly.
The team found that viruses adapt more rapidly than their microbial hosts when exposed to drought. As soil moisture decreased, the viral community composition shifted, and types of viruses predicted to infect drought-adapted actinobacteria became more dominant. “Despite a large amount of spatial turnover, viruses responded cohesively to changing environmental conditions,” said project colead Katerina Estera-Molina. The research was published in the November 8, 2022, issue of Proceedings of the National Academy of Sciences. “Characterizing the compositional response of soil viral communities to reduced precipitation can help us understand the impact of a changing environment on host–virus interactions and potential downstream effects on the soil-carbon cycle,” said Pett-Ridge. Estera-Molina and Pett-Ridge are both microbial ecologists at the Laboratory who are also affiliated with UC.
Contact: Jennifer Pett-Ridge (925) 424-2882 (pettridge2@llnl.gov).
