The research progress on the safety of lithium batteries is as follows:
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Improved Electrolyte Safety:
- A research team from the University of Science and Technology of China found that the interaction of intermolecular hydrogen bonds can significantly improve the stability of ether-based electrolytes at the electrode interface and effectively inhibit the thermal runaway process of lithium metal batteries. They proposed a new molecular anchoring strategy, which can not only improve the high-voltage performance of the electrolyte but also enhance its safety. In a lithium metal soft-pack battery, the molecular anchored electrolyte can increase the temperature at which thermal runaway begins to above 209 degrees Celsius.
- The Beijing Institute of Technology's Huang Jiaqi professor's research group developed an in-situ polymerized solid-state electrolyte with high thermal stability and electrochemical compatibility with lithium metal anodes. This electrolyte can improve the safety performance of the battery and enable the solid-state metal lithium battery to have excellent cycle stability at high temperatures and high cut-off voltages.
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Enhanced Separator Safety:
- Scientists from Incheon National University developed a method to improve the stability and performance of lithium-ion battery separators by graft polymerization. The modified separator shows better thermal stability and the ability to resist the growth of lithium dendrites, reducing the risk of internal short circuits and improving battery performance.
- Researchers from the Institute of Modern Physics of the Chinese Academy of Sciences and the Guangdong Laboratory of Advanced Energy Science and Technology have successfully developed a high-temperature-resistant polyethylene terephthalate (PET) separator for lithium-ion batteries using heavy ion irradiation technology and chemical etching processes. This separator has more uniform pore size distribution, better electrolyte wettability, and good high-temperature resistance performance compared to commercial polyolefin separators.
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New Solid-State Electrolyte Materials:
- A Japanese team discovered a new material called "pyrochlore-type oxyfluoride," which can not only allow lithium ions to migrate efficiently and improve conductivity but also maintain excellent conductivity at extreme temperatures. It does not leak or produce toxic gases when damaged, which is much better than the solid-state batteries currently on the market. This material has broad application prospects in the field of all-solid-state lithium batteries.
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Safety Standards and Regulations:
- In China, many regions have formulated local technical standards for the safety of lithium batteries used in electric vehicles, and a mandatory national standard is also about to be released. This standard will stipulate 33 safety technical indicators such as overcharging and overdischarging of single batteries, temperature protection and overcharging protection of battery packs, which will further improve the safety of lithium batteries.The research team of Qingdao Institute of Bioenergy and Process, Chinese Academy of Sciences has made a major breakthrough in the field of sulfide electrolyte research, successfully preparing ultra-thin sulfide solid electrolyte membrane by dry method to make lithium batteries safer.