Oak Ridge Today

‘Double-duty’ electrolyte enables new chemistry for longer-lived batteries

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ORNL Battery Chemistry

When ORNL researchers incorporated a solid lithium thiophosphate electrolyte into a lithium-carbon fluoride battery, the device generated a 26 percent higher capacity than what would be its theoretical maximum if each component acted independently. (Image courtesy ORNL)

 

Researchers at Oak Ridge National Laboratory have developed a new and unconventional battery chemistry aimed at producing batteries that last longer than previously thought possible.

In a study published in the Journal of the American Chemical Society, ORNL researchers challenged a long-held assumption that a battery’s three main components—the positive cathode, negative anode, and ion-conducting electrolyte—can play only one role in the device.

The electrolyte in the team’s new battery design has dual functions: It serves not only as an ion conductor but also as a cathode supplement. This cooperative chemistry, enabled by the use of an ORNL-developed solid electrolyte, delivers an extra boost to the battery’s capacity, and extends the lifespan of the device.

“This bi-functional electrolyte revolutionizes the concept of conventional batteries and opens a new avenue for the design of batteries with unprecedented energy density,” said ORNL’s Chengdu Liang. [Read more…]

‘Atomic switcheroo’ explains origins of thin-film solar cell mystery

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Current Maps

Cross-sectional electron beam-induced current maps show the difference in cadmium telluride solar cells before (pictured above) and after (below) cadmium chloride treatment. The increased brightness after treatment indicates higher current collection at the grain boundaries. (Submitted photo)

Treating cadmium-telluride (CdTe) solar cell materials with cadmium-chloride improves their efficiency, but researchers have not fully understood why. Now, an atomic-scale examination of the thin-film solar cells led by Oak Ridge National Laboratory has answered this decades-long debate about the materials’ photovoltaic efficiency increase after treatment.

A research team from ORNL, the University of Toledo, and the U.S. Department of Energy’s National Renewable Energy Laboratory used electron microscopy and computational simulations to explore the physical origins of the unexplained treatment process. The results are published in Physical Review Letters, or PRL.

Thin-film CdTe solar cells are considered a potential rival to silicon-based photovoltaic systems because of their theoretically low cost per power output and ease of fabrication. Their comparatively low historical efficiency in converting sunlight into energy, however, has limited the technology’s widespread use, especially for home systems. [Read more…]

ORNL-grown oxygen ‘sponge’ presents path to better catalysts, energy materials

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ORNL Oxygen Sponge

This schematic depicts a new ORNL-developed material that can easily absorb or shed oxygen atoms. (Photo courtesy ORNL)

Scientists at Oak Ridge National Laboratory have developed a new oxygen “sponge” that can easily absorb or shed oxygen atoms at low temperatures. Materials with these novel characteristics would be useful in devices such as rechargeable batteries, sensors, gas converters, and fuel cells.

Materials containing atoms that can switch back and forth between multiple oxidation states are technologically important but very rare in nature, said ORNL’s Ho Nyung Lee, who led the international research team that published its findings in Nature Materials. [Read more…]