Science & Technology

Selective membranes have the potential to circulate near-realistic dual-ion batteries

Schematic of a comparison of EMC simultaneous intercalation behavior in LE (a) or PCME (b) based DIBs. Credit: Jiang Hongzhu

Lithium-ion batteries are relatively safe, long-lasting, fast-chargeable, and more environmentally friendly than non-rechargeable batteries. Not perfect. Rocking chair mechanisms that enable commercial power storage generally use rare earth elements such as nickel and cobalt.

Researchers have long sought alternative batteries that boast all the benefits of the lithium-ion version, but with ecological and economic benefits.

Currently, the team at the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) at the Chinese Academy of Sciences (CAS) is approaching an improved approach. They provided a solution to a problem called the “notorious problem” that causes the system to malfunction when the battery is recharged and discharged. cycling..

Their research is Advanced material December 24th.

Dual-ion batteries (DIBs) are receiving a great deal of attention due to their non-transition metal composition, economy and environmental friendliness. “The actual implementation of DIB technology is mostly stagnant, primarily due to rapid battery failure during high voltage cycling,” said Jiang Hongzhu, lead author of the CAS QIBEBT PhD candidate. increase.

In DIB, positively and negatively charged ions are simultaneously charged. Electrolytes— A liquid or film that disperses the ions of the dissolved material and conducts them electrically throughout the space — on the opposite electrode. According to Mr. Jiang, the “notorious problem” is that the solvent used for the electrolyte can be inserted into the graphite layer of the electrode due to the interaction between the anion and the solvent.

“Ultimately, the simultaneous intercalation of this solvent results in the exfoliation and grinding of graphite at high potentials, especially in the widely used linear carbonate electrolytes,” said Jiang. She also pointed out that high-voltage cycling can also lead to the oxidation of thermodynamically unstable electrolytes. Previous strategies focused on increasing electrolyte stability did not effectively address the critical problem of simultaneous solvent intercalation.

To prevent co-insertion and electrolyte corrosion, researchers needed to separate negatively charged anions from the solvent. A viable approach is to modify the anionic solvation structure by introducing into the electrolyte another component that interacts more strongly with the anion than the carbonate solvent.

Researchers have focused on the anionic component hexafluorophosphate. Lithium ion battery.. They adopted key monomers containing positively charged quaternary ammonium motifs to develop polyelectrolyte membranes capable of selectively filtering anions. It provided excellent cycling stability with 99% Coulomb efficiency at high voltage.

“This strategy significantly suppresses simultaneous solvent intercalation, increases the oxidation resistance of the electrolyte, and ensures the structural integrity of graphite,” said Cui Guanglei, professor of QIBEBT at CAS, the author of the paper. I am saying. “we, Anion Desolvation is important for improving the long cycling performance of DIBs. ”

Solvation rearrangement brings stable zinc / graphite batteries closer to commercial grid storage

For more information:
Hongzhu Jiang et al, A PF 6-Selective Permeable Polyelectrolyte with Anion Solvation Adjustment Allowing Long Cycle Dual Ion Batteries, Advanced material (2021). DOI: 10.1002 / adma.202108665

Quote: Selective membrane is a near-realistic dual-ion battery acquired from https: // on January 19, 2022. May be circulated (January 19, 2022)

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Selective membranes have the potential to circulate near-realistic dual-ion batteries Selective membranes have the potential to circulate near-realistic dual-ion batteries

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