Super cheap land element to advance the new battery technology in the industry

WEST LAFAYETTE, Ind. – Most of the batteries of today are composed of rare lithium extracted from the mountains of South America. If the world exhausts this source, then the production of batteries could stagnate.

Sodium is a very cheap and abundant alternative to the earth using lithium-ion batteries that are also known to become violets and burn if they are exposed to water – even just water in the water. # 39; air.

Global efforts to manufacture sodium-ion batteries that are as functional as lithium-ion batteries have long been controlling the trend of sodium explosion, but have not yet resolved how to prevent sodium ions from occurring. "lose" Now, researchers at Purdue University have come up with a version of sodium powder that solves this problem and keeps a charge properly.

"The addition of sodium powder manufactured during electrode processing only requires slight modifications to the battery production process," said Vilas Pol, Associate Professor of Chemical Engineering at Purdue. "This is a potential way to advance sodium ion battery technology in the industry."

The study was put online in June 2018 before printing on August 31, 2018 in the Journal of Energy Sources.

This work is part of Purdue's giant celebrations, highlighting the university's global advances in health, space, artificial intelligence and sustainable development in the context of 150th anniversary of Purdue. These are the four themes of the festival of ideas celebrated throughout the year, designed to present Purdue as an intellectual center solving real world problems.

Although sodium-ion batteries are physically heavier than lithium-ion technology, researchers have studied sodium-ion batteries because they could store energy for large solar and wind systems at a lower cost .

The problem is that sodium ions stick to the hard end of a battery's carbon, called anode, during initial charge cycles and do not move to the end of the cathode. The ions are transformed into a structure called "solid electrolyte interface".

"Normally, the interface of the solid electrolyte is good because it protects the carbon particles from the acidic electrolyte of the battery, where electricity is conducted," Pol said. "But too much interface consumes the sodium ions we need to charge the battery."

Purdue researchers have proposed using sodium in powder form, which provides the required amount of sodium for the solid electrolyte interface to protect the carbon, but does not accumulate so as to consume sodium ions.

They minimized the exposure of sodium to moisture that would burn it by making sodium powder in a glove box filled with gaseous argon. To make the powder, they used an ultrasound – the same tool used to monitor the development of the fetus – to melt sodium lumps into a milky purple liquid. The liquid is then cooled to a powder and is suspended in a hexane solution to uniformly disperse the powder particles.

Only a few drops of the sodium suspension on the anode or cathode electrodes during their manufacture allow a sodium ion battery cell to charge and discharge with more stability and greater capacity.

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A provisional US patent has been filed for this technology. The work was supported by the Innovation Fund of Purdue University.

ABSTRACT

Ultrasonic assisted synthesis of sodium powder as an electrode additive to improve the cyclic performance of sodium-ion batteries

Jialiang Tang, Daniel Kyungbin Kye and Vilas G. Pol

Purdue University, West Lafayette, IN, USA

doi: 10.1016 / j.jpowsour.2018.06.067

Solid electrolyte interphase buildup (SEI) in formation cycles or subsequent cycles consumes electrolyte, depletes the availability of alkaline ions and increases cell polarization; reducing the amount of alkaline ions available during cycling often results in low capacity and low retention in the solid cells. To compensate for Na loss from SEI formation, we developed a sodium powder pre-sodiation technique that could be applied to both anodic and cathodic materials with minimal modification of the conventional fabrication process. The synthesis of the sodium powder is carried out by ultrasonic dispersion of molten sodium metal in mineral oil. Suspended in hexane, the sodium powder can be easily applied to electrodes as a pre-sodiation additive. In the study of half-cells with glucose-derived carbon (GC1100), pre-sodiation decreases the initial potential of the cell in open circuit (1 1 V drop) and reduces irreversible Coulomb efficiency first cycle (from 19.3% to 8%). In the complete cell study with GC1100 and NaCrO2, pre-sodiation results in a 10% improvement in cycling capacity and a 5% increase in energy density. A decrease in cell polarization is also observed in pre-soded cells.