A team of researchers designed and manufactured a new sodium ion conductor for solid-state sodium ion batteries, all of which are stable at high voltage oxide cathodes. This new solid electrolyte could dramatically improve the efficiency and life of this battery class. The proof of the concept of the battery built with the new material lasted more than 1000 cycles maintaining its capacity of 89.3%, which until now had been unmatched by other solid state sodium batteries.
The researchers determined the findings on February 23, 2021 Nature Communications.
Solid state batteries promise safer, cheaper, and longer lasting batteries. Sodium-ion chemicals are particularly promising because sodium is low-cost and plentiful, compared to the lithium-ion batteries required for lithium-ion batteries, as it comes at a high environmental cost. The goal is to build batteries that can be used in high-energy energy storage applications, primarily to alleviate the higher energy demand generated by renewable energy.
“The industry wants cells at the cellular level, between $ 30 and $ 50 per kWh,” said one-fifth to one-fifth of what it currently costs, said Shirley Meng, a professor of nanoengineering at the University of California, San Diego and author of the paper. “We won’t stop until we get there.”
The ZrCl6 unit is shown to rotate, creating gaps, which increases conductivity. Credit: University of California
Work at UC San Diego and UC Santa Barbara, Stony Brook University, TCG Center for Research and Education in Science and Technology in Kolkata (India) and Shell International Exploration, Inc. it is a collaboration between researches.
In terms of the battery described in the Nature Communications study, researchers led by San Diego nanoengineering professor Shyue Ping Ong UC performed some computational simulations to feed a machine learning model on which chemical would have the right combination of properties for a solid state battery cathode oxide. After selecting a material as a good candidate, Meng’s research team experimentally fabricated, tested, and characterized it to determine its electrochemical properties.
Repeating rapidly between the calculation and the experiment, the UC SanDiego group was placed in a class of sodium halide conductor consisting of sodium, yttrium, zirconium, and chloride. The material was designated NYZC as being electrochemically stable and chemically compatible with the oxide cathodes used in high-voltage sodium ion batteries. The team approached researchers at UC Santa Barbara to study and understand the structural properties and behavior of this new material.
NYZC is based on Na3YCl6, a well-known material that is unfortunately a very poor conductor of sodium. Ong proposed replacing zirconium with yttrium because it would create gaps and increase the volume of the cell battery unit, two approaches that increase the conduction of sodium ions. The researchers also noted that, along with the increased volume, the combination of zirconium and chloride ions in this new material results in rotational motion, resulting in more sodium ion conduction pathways. In addition to increasing conductivity, the halide material is much more stable than the materials currently used in sodium batteries in the solid state.
“These findings highlight the tremendous potential of halide ion conductors for solid-state sodium ion battery applications,” Onge said. “It also highlights the transformative impact that large-scale material data calculations can have on machine learning in the process of finding materials.”
The next steps include examining other substitutes for these halide materials and increasing the overall power density of the battery, along with work to increase the manufacturing process.
Reference: Erik A. Wu, Swastika Banerjee, Hanmei Tang, Peter M. Richardson, Jean-Marie Doux, “A stable compound for solid-state ion batteries for high-voltage and long-cycle life. Ji Qi, Zhuoying Zhu, Antonin Grenier, Yixuan Li, Enyue Zhao, Grayson Deysher, Elias Sebti, Han Nguyen, Ryan Stephens, Guy Verbist, Karena W. Chapman, Raphaële J. Clément, Abhik Banerjee, Ying Shirley Meng and Shyue Ping Ong , February 23, 2021, Nature Communications.
DOI: 10.1038 / s41467-021-21488-7
The technology has been licensed by UNIGRID, a startup created by UC San Diego NanoEngineering Professor Zheng Chen; Dr. Erik Wu is a former student of the Meng research team; and Darren HS Tan, one of Dr. Meng. students. Meng is a technical consultant for the company.
Funding to support this work was provided by the Energy & Biosciences Institute through the EBI-Shell program and the NSF.