18650 li ion rechargeable battery

　　A Chinese research team synthesized a single-layer graphene electrode that can solve the problem of lithium dendrite growth

　　According to reports, a joint research team from the Academy of Special Sciences, Peking University and other units synthesized a perfect single-layer graphene electrode and revealed the electrodeposition behavior of lithium atoms using it as a base material, filling the gap between metallic lithium on the carbon atom lattice. The gap in basic research on heterogeneous nucleation provides a theoretical basis for solving problems such as lithium dendrites encountered in the industrialization of lithium batteries. Relevant papers were recently published online in the magazine "Energystorage Materials".

　　Lithium dendrites can grow in liquid lithium batteries, puncturing the separator and causing a short circuit in the battery. Zhang Hao, associate researcher at the Academy of Special Sciences, a member of the research team, said that recent research has used porous carbon-based materials to construct a metallic lithium anode skeleton to inhibit the growth of lithium dendrites, but the rules are disordered and the effect is limited. One of the reasons is the lack of basic research on the nucleation of metallic lithium on carbon lattices by electrodeposition in the academic community.

　　To understand how metallic lithium is deposited on the carbon lattice, a pure, background-free growth environment must be obtained. To this end, Professor Peng Hailin of Peking University in the team created a perfect base surface of carbon atoms and used chemical vapor deposition to grow a single layer of graphene on copper foil. Meng Qianqian, the first author of the paper and a member of the team, introduced that single-layer graphene can be used to eliminate the interference of all coupling factors brought by porous carbon on lithium deposition, thereby achieving a clear understanding of the heterogeneous nucleation behavior of metallic lithium on the carbon lattice. Interpretation.

　　On this basis, the research team conducted a series of basic theoretical explorations through ex-situ scanning electron microscopy observations and other methods and found that compared with traditional metal current collectors (components that collect current in batteries), the formation of lithium on a perfect carbon base surface is The nucleation barrier is higher and more difficult to nucleate, so graphene replaces metal as a current collector or has an inhibitory effect on crystallization.

　　The team also observed that defects such as dislocations on the carbon lattice can promote lithium nucleation, and there is secondary nucleation of lithium at the intersection of lithium dendrites. These results will help to understand the related mechanisms of metallic lithium nucleation on the carbon atom lattice and lithium dendrite growth, and then produce more effective design strategies for metallic lithium anodes with three-dimensional carbon skeletons to solve the problem of lithium dendrite growth.

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