The reporter was informed on the 15th that a joint research team of the Academy of Military Sciences and Peking University synthesized a perfect single-layer graphene electrode and revealed the behavior of lithium atoms as a base material for electrodeposition, filling the metal lithium in the carbon atom crystal. The basic research gap of heterogeneous nucleation on the grid provides a theoretical basis for solving the problems of lithium dendrite encountered in the industrialization of lithium batteries. Related papers were recently published online in the journal Energy Storage Materials.
'Lithium dendrites' will grow in liquid lithium batteries, pierce the diaphragm, causing short-circuit of the battery. Zhang Hao, an associate researcher of the Academy of Military Sciences of the research team, introduced the method of constructing lithium metal anode skeleton by porous carbon-based materials in recent years. Crystal growth, but the law is disordered, the effect is limited. One of the reasons is the gap in the basic research of the electrodeposition nucleation of metallic lithium on the carbon lattice.
To clarify how metal lithium is deposited in the carbon lattice, a pure, no-background interference environment must be obtained. To this end, the team's Peking University Professor Peng Hailin's project has become a perfect carbon atom base, using chemical vapor deposition. A single layer of graphene is grown on the copper foil. The first author of the paper, Meng Qianqian, a team member, introduced that single-layer graphene can be used to eliminate the interference of lithium coupling caused by all the coupling factors of porous carbon, and thus realize the metal lithium in carbon. A clear interpretation of the heterogeneous nucleation behavior on the lattice.
On this basis, the research team conducted a series of basic theoretical explorations through non-in-situ scanning electron microscopy and other methods. Compared with traditional metal current collectors (components that collect current in batteries), lithium is formed on a perfect carbon surface. The nuclear barrier is higher and more difficult to nucleate. Therefore, graphene is substituted for metal as a current collector or inhibits 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 form lithium metal on the lattice of carbon atoms. The understanding of nuclear, lithium dendrite growth and other related mechanisms, and then the more effective three-dimensional carbon skeleton of the lithium metal anode design strategy to solve the problem of lithium dendrite growth.
