With the rapid development of portable electronic devices and electric vehicles, people are more concerned with the safety of lithium batteries in addition to the large capacity of lithium batteries and the speed of charge and discharge. The frequent lithium battery explosion accidents inevitably make people nervous. From a scientific point of view, lithium battery explosion is usually caused by non-uniform lithium deposition on the electrode surface led to dendrites, resulting in reduced charge-discharge efficiency of the battery, or even a short circuit inside the battery, causing a battery failure or potential safety hazard .
Scientists are trying to find a solution Recently, Chinese scholars proposed using a microspheres structure to capture lithium to limit lithium deposition and dendrite growth.
As the growth of dendrites is suppressed, the electrode can still maintain a high plating / stripping efficiency of 99% after more than 200 times of charging and discharging. This not only helps to prolong the life of the lithium battery, but also effectively enhances the safety.
The above research comes from Guo Yuguo, a researcher at the Key Laboratory of Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, which was published in the journal American Chemistry Society Nano Letters.
Picture from Guo Yu Guo and others in Nano Letters published papers
The specific method proposed by Guo Yuguo's team is to capture lithium through the microsphere so as to limit the deposition and inhibit the growth of dendrites.The microspheres prepared by the method are composite materials of the carbon nanotube and the porous silica protective layer, Experiments show that the composite structure of this structure is very effective in controlling the lithium deposition behavior.In addition, the insulating coating can also prevent the concentration of electrons flow and reduce the possibility of forming 'hot spots'.
It is known that Guo Shaojun's group designed a silica-based ionic gel electrolyte modified by a special functional group by learning from the characteristics that the anthill of the natural world can rapidly exchange air. The bionic ion gel electrolyte has the advantages of fast The ability to transport lithium ions and the ability to spontaneously form a particle-rich layer on the surface of the lithium metal negative electrode to effectively inhibit the growth of lithium dendrites.This result provides a new idea for designing a high-performance lithium metal battery using the bionic concept .
Guo Yuguo team believes that this study for the lithium metal electrode design provides a new way to accelerate the practical application of lithium batteries.
Previously, in solving this safety issue of lithium batteries, the industry is using more electrolyte additives, stable interface and modified electrodes and other ways.Experiments have shown that the use of architecture to adjust the lithium dendrite accumulation is the most efficient way.
Guo Shaojun from Peking University's Institute of Engineering and Chen Renjie from Beijing Institute of Technology jointly proposed a method of inhibiting lithium dendrites through the solid ant 'structure solid electrolyte. The team's research paper was published in June 2017 in the international academic journal Energy And Environmental Science "(Energy & Environmental Science) officially published.