On the national natural science foundation project, the project of lift for young scientists of China association for science and technology and Beijing institute of technology, with the support of science and technology innovation plan of Beijing university of science and technology special Huang Jiaqi cross frontier science research institute researcher team in the next generation of high energy density of metal lithium battery lithium metal anode high security research has made new progress. Related research results in recent entitled "Artificial soft - it rigid protective layer for dendrite - free lithium metal anode" on January 8, 2018, published online in the journal of Advanced Functional Materials, Advanced Functional Materials, the impact factor of 12.124).
Lithium metal because of its high theoretical specific capacity (3860 mA h g - 1) and the negative electrode potential (3.045 V - vs. standard hydrogen electrode) and is considered to be one of the most development prospects of anode materials ratio can. But practical lithium metal electrode by lithium dendrite growth and lower limit cycle efficiency. Lithium metal is a kind of high active metal, formed when in contact with the electrolyte, complex structure and components of solid electrolyte interface in the process of electrochemical reaction is difficult to maintain the stability of the interface. As a result, the uneven sedimentation of lithium ion easy cause needle, dendritic, moss of lithium deposits. Lithium dendrite growth on the one hand will puncture the diaphragm, contact with the anode lead battery short circuit, cause safe hidden trouble; On the other hand also increases the lithium metal and the electrolyte contact area, makes the side effects, the cycle efficiency of the battery down further.
"Flexibility" of the composite membrane by modifying interface, to cling to the surface of metallic lithium can effectively, and inhibit the growth of dendritic diagram
In order to build stable metal lithium/electrolyte interface, regulate the uniform deposition of lithium, the group put forward with inorganic LiF as rigid components, based on PVDF HFP - polymer flexible components to build "gentleness" composite membrane, to in the process of electrochemical cycle stability of metallic lithium and electrolyte interface. Among them, the flexible polymer provides flexibility and scalability of affordable lithium metal electrode interface fluctuations in the process of deposition/dissolve, and the introduction of rigid components can further enhance the mechanical modulus of the modified layer, thus inhibiting the lithium dendrite growth, achieve uniform deposition of lithium. Will this also has better deformation performance, high mechanical modulus and ionic conductivity of interface modification is introduced into the button battery, Li - Cu half cell, Li - Li symmetrical cycle life of battery and cycle stability are significantly increased; With lithium iron phosphate anode matching the whole battery of tests, the compound layer after the modification of the battery cycle life increased 2.5 times.