The reporter learned on the 15th that the joint research team of the Academy of Military Sciences, Peking University and other units synthesized a perfect single-layer graphene electrode, and revealed the behavior of electrodeposition of lithium atoms using it as a base material, filling the lithium metal in carbon atoms. The basic research gap of heterogeneous nucleation on the grid provides a theoretical basis for solving the problems of lithium dendrites encountered in the industrialization of lithium batteries. Related papers have recently been published online in the journal "Energy storage materials".
"Lithium dendrites" will grow in liquid lithium batteries and pierce the separator, causing a short circuit in the battery. Associate researcher Zhang Hao of the Academy of Military Sciences, a member of the research team, said that recent studies have used porous carbon-based materials to construct metal lithium anode frameworks to inhibit the growth of lithium dendrites, but the rules are disordered and the effect is limited. One of the reasons is the blank of basic research in the academic circles on the nucleation of lithium metal electrodeposition on a carbon lattice.
To clarify how metallic lithium is deposited on the carbon lattice, it is necessary to obtain a pure, background-free growth environment. To this end, the subject of Professor Peng Hailin of Peking University in the team formed a perfect carbon atom base surface, and a single layer of graphene was grown on the copper foil by chemical vapor deposition. The first author of the paper and team member Meng Qianqian introduced that single-layer graphene can be used to eliminate the interference of all the coupling factors brought by porous carbon on the deposition of lithium, and thus realize the clear heterogeneous nucleation behavior of lithium metal on the carbon lattice Interpretation.
On this basis, the research team conducted a series of basic theoretical explorations through ex-situ scanning electron microscopy and other methods. Compared with traditional metal current collectors (components that collect current in batteries), the formation of lithium on the perfect carbon base surface The nuclear barrier is higher and it is more difficult to nucleate, so graphene replaces the 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 secondary nucleation of lithium at the junction of lithium dendrites. These results will help to understand the related mechanisms of lithium metal nucleation on the carbon atom lattice, lithium dendrite growth, etc., and then produce a more effective three-dimensional carbon skeleton metal lithium anode design strategy to solve the problem of lithium dendrite growth.
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