A research team composed of Cui Yi, a well-known materials scientist at Stanford University in the United States, and Zhu Diwen, a former US Secretary of Energy and Nobel Prize winner in physics, has recently achieved a major breakthrough in the practical use of lithium metal electrodes.
The research team with PhD student Liang Zheng as the backbone put forward the concept of lithium-philicity for the first time, and successfully prepared a composite metal lithium electrode by using the carbonaceous host material solved by surface lithophilization, which can greatly improve the performance of lithium-ion batteries. .
In recent years, with the rapid development of portable electronic equipment, electric vehicles and renewable energy, high-energy energy storage devices have become one of the research hotspots in the field of new energy and new materials. Lithium metal has a very high theoretical specific capacity and an ideal negative electrode potential. Secondary batteries with lithium metal as the negative electrode have the advantages of high working voltage and high energy density, making metal lithium the preferred material in the field of energy storage today. However, various indicators of the existing lithium-ion secondary batteries, such as capacity, cycle life, charging speed, etc., cannot meet the increasing demands of consumers. Therefore, the development of new electrode materials has become a top priority.
The newly researched composite metal lithium electrode has small dimensional changes, extremely high specific capacity and good cycle and rate performance during the cycle of carbonate electrolyte system. Its voltage curve is also relatively smooth, breaking the current restrictions on metals. The important issues for the large-scale commercialization of lithium-ion batteries are side reactions between metallic lithium and electrolyte, changes in electrode size during cycling, and the formation of lithium dendrites. The former greatly reduces the coulombic efficiency of the battery and affects its electrochemical performance; the latter two will bring serious safety hazards to metal lithium-ion batteries.
In response to the above problems, the team launched a series of studies. After many attempts, they turned their attention to nanotechnology. After conducting in-depth research on the special wettability of the material surface, the research team proposed the concept of lithium-philicity for the first time, and used the carbonaceous host material solved by surface lithiation to create a lithium-philic interface material system, which pioneered the transformation of metal After the lithium is melted, the capillary is used to suck into the voids of the carbon fiber network, and a composite metal lithium electrode containing a supporting frame is successfully prepared.
The composite metal lithium electrode is composed of 10% by volume of carbon fiber and metal lithium material. Carbon fiber network has good electrical conductivity, ultra-high mechanical strength and electrochemical stability, so it is an excellent choice as the main frame material of metal lithium. Compared with previous related researches, Liang Zheng et al. melted lithium metal and proposed the concept of lipophilic lithium based on the wettability of different materials, which provided new ideas for the research of lithium metal electrodes, and has a great deal of research in other fields. Very high reference use.
After the team’s research results were published online in the Proceedings of the National Academy of Sciences in the United States, it has received widespread attention in the industry. Many media have followed up and reported on it, which is considered a major breakthrough in the field of lithium-ion battery research. Now this research result has applied for a US invention patent.
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