Major breakthroughs made in research on lithium batteries

　　Researchers at Tsinghua University in China recently published a lithium metal electrode material based on graphene nanostructures that can be used to inhibit dendritic growth in lithium metal batteries and further improve their electrochemical performance.

　　Researchers from Tsinghua University in China have recently published a lithium metal electrode material based on graphene nanostructures that can be used to inhibit dendritic growth in lithium metal batteries and further improve their electrochemical performance. "Currently widely used lithium-ion batteries are increasingly difficult to meet the increasing energy storage requirements of portable electronic products and electric vehicles (EV). Such as lithium-sulfur batteries (Li-S) and lithium-air batteries (Li-air). New lithium-ion metal anode batteries are also very popular. Lithium metal batteries provide extremely high theoretical performance, almost 10 times more energy than graphene," said Zhang Qiang, associate professor of the Department of Chemical Engineering at Tsinghua University. "However, under continuous cycles, the practical application of lithium metal is strongly disturbed by the growth of lithium dendrites, and even raises safety concerns. Lithium dendrites may cause a short circuit within the battery and cause fire. Moreover, the formation of lithium dendrites is also The cycle efficiency is reduced. "　　 Dendrite growth and instability of the solid electrolyte interface will consume a large amount of lithium and electrolyte, resulting in irreversible battery capacity loss.　　In order to alleviate the growth of dendrites, several methods have been developed, including adjusting electrolyte, using artificial solid electrolyte interface layer and electrode structure, etc. "We found that by greatly reducing the local current density, the growth of lithium dendrites can be effectively inhibited. Based on this concept, we used non-stacked graphene materials with ultra-high specific surface area to create a nanostructured anode. The results show that This is a very effective method," explained Rui Zhang, a PhD student in chemical engineering at Tsinghua University and the lead author of the study. "In addition, we use double salt electrolyte to achieve a more stable and flexible solid electrolyte interface to avoid lithium metal. It further reacts with the electrolyte. "　　 Graphene-based anodes have brought many advancements, including the large specific surface area of 1666m2g-1, which results in ultra-low local current density on the surface of the graphene anode (only when copper foil anodes are used) One in ten thousand), while inhibiting the growth of dendrites, resulting in a uniform lithium deposition morphology. Due to the high pore capacity (1.65cm2g-1) of non-stacked graphene, this anode can also provide a high stable cycle performance of 4.0mAhmg-1, which is higher than the graphene anode (0.372mAhmg-1) in lithium-ion batteries. Times.　　The anode also exhibits high conductivity (435Scm-1), which brings low interface impedance, stable charge/discharge performance, and high cycle efficiency.　　 "The conductive nanostructured anode with high specific surface area brings ultra-low local current density, which will help improve the stability and electrochemical performance of lithium metal anodes," said Xin-BingCheng, another author of the study. Relevant research results have been published in the latest issue of "Advanced Materials" (Advanced Materials).