Scientists design electrolyte for met lithium

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image: Schematic of the ion distribution of the high interfacial concentration electrolyte (top left) and the discharge/charge voltage profiles of the conventional concentration electrolyte and the high interfacial concentration electrolyte (top to the right). The schematic at the bottom of the image illustrates the effect of high concentration interfacial electrolyte on lithium nucleation and plating.
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Credit: Nano Research, Tsinghua University Press

With the growing demand for electric vehicles, the need for high-security and long-lasting batteries is also increasing. Yet the demand from electric vehicles for high-energy-density batteries exceeds the capabilities of current lithium-ion batteries. Scientists are looking to develop lithium metal batteries with lithium metal as the anode because these batteries have a much higher charge capacity. However, lithium-metal batteries present safety issues because dendrites, sharp metallic microstructures, form during the charging process.

A team of Chinese researchers set out to solve the problem of lithium dendrite formation and build high-safety, long-life lithium metal batteries. The team succeeded in designing an electrolyte that suppresses the formation of dendrites. This electrolyte offers excellent performance in lithium metal batteries and offers solutions in research for the construction of high safety and long life lithium metal batteries.

The team’s findings are published in the journal Nano-research on October 3, 2022.

While lithium metal anodes show great potential for high-energy storage batteries, the uncontrollable growth of lithium dendrites raises significant concerns. Dendrite growth occurs when lithium ions move and convert at a specific location on the surface of metallic lithium. Dendrites lead to low cycling efficiency in the battery and are a serious safety issue.

The team tackled the problem of dendrites by combining the advantages of conventional electrolytes and high-concentration electrolytes. High concentration electrolytes overcome some of the shortcomings of conventional electrolytes and hold great promise for use in next-generation batteries. The electrolyte created by the team provides excellent electrochemical performance in lithium metal batteries and suppresses the formation of dendrites. “Its unique structure not only promotes the uniform conversion of ions on the electrode surface, but also ensures the rapid movement of ions in the electrolyte,” said Chunpeng Yang, a professor at Tianjin University.

The researchers began their work by running numerical simulations to explore the effect of a negatively charged coating to induce the high interfacial concentration electrolyte. Then, as a proof-of-concept material, the researchers coated nitrogen- and oxygen-doped carbon nanosheets, which have negative surface charges, with nickel foam to create the electrode. Positively charged lithium ions are concentrated near the nickel-coated nitrogen-oxygen doped carbon electrode. This concentration of lithium ions promotes charge transfer reactions on the electrode contributing to exceptional electrochemical cycling performance. The researchers performed half-cell and full-cell tests on the electrode with excellent results. Their electrode is much more efficient than other electrodes based on pure nickel foam.

“This provides a simple principle to remove lithium dendrites by simultaneously considering the advantages of conventional electrolyte and high concentration electrolyte for the stable Li metal anode, which can be applied to other substrates for the convenient metal batteries,” Yang said.

Beyond coating surface negatively charged materials on the electrode to guide the formation of high-concentration interfacial electrolytes, the team plans to research other ways to achieve this unique electrolyte structure as a way to get high performance batteries. The researchers hope to achieve the commercial application of Li metal batteries with high energy density, high safety and long life, by systematically optimizing battery components. “The results of our study could be extended to more metal battery systems, such as sodium, zinc and magnesium metal batteries, which will contribute to the realization of large-scale energy storage for energy supply. sustainable energy,” Yang said.

The research team includes Haotian Lu, Feifei Wang and Lu Wang from Tianjin University, Haihe Laboratory of Sustainable Chemical Transformations and National University of Singapore; Chunpeng Yang, Tianjin University and the Haihe Laboratory of Sustainable Chemical Transformations; Jinghong Zhou of East China University of Science and Technology; Wei Chen, National University of Singapore; and Quan-Hong Yang of Tianjin University and the Haihe Laboratory of Sustainable Chemical Transformations.

This research is funded by the National Key Research and Development Program of China, the Haihe Laboratory of Sustainable Chemical Transformations and the Fundamental Research Funds for the Central Universities.

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About Nano-research

Nano-research is an international and interdisciplinary peer-reviewed research journal, publishes all aspects of nanoscience and technology, presented in a rapid review and rapid publication, sponsored by Tsinghua University and the Chinese Chemical Society. It offers readers an engaging mix of comprehensive, authoritative reviews and cutting-edge original research articles. After 15 years of development, it has become one of the most influential academic journals in the field of nanos. In 2022 InCites Journal Citation Reports, Nano-research has an impact factor of 10,269 (9,136, 5 years), the total number of citations reached 29,620, ranking first in Chinese international academic journals, and the number of highly cited papers reached 120, ranked in the top 2.8% of over 9,000 academic journals.

About Tsinghua University Press

Founded in 1980, owned by Tsinghua University, Tsinghua University Press (TUP) is one of the leading comprehensive professional and higher education publishers in China. Committed to building a high-level global cultural brand, after 41 years of development, TUP has established an outstanding management system and corporate structure, and delivered multi-media and multi-dimensional publications covering books, audio, video, electronic products, magazines and digital publications. . In addition, TUP is actively leading its strategic transformation from educational publishing to content development and service for teaching and learning and was named a National First Class Publisher for achieving outstanding results.


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