Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institution of New Energy, Collaborative Innovation Center of Chemistry for Energy Materials , Fudan University , Shanghai 200433 , China.
Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455-0431 , United States.
ACS Appl Mater Interfaces. 2019 Mar 20;11(11):10616-10623. doi: 10.1021/acsami.8b19654. Epub 2019 Mar 7.
The development of Li metal anodes is hindered by the Li dendrites arising from the random deposition of Li metal during cycles. Hence, uniform deposition of Li during repeated cycles is crucial for the development of Li metal batteries. However, it is difficult to regulate Li deposition because of convection in the electrolyte. Here, we employ a dual lithiophilic structure composed of a polar metal-organic framework (MOF) and highly conductive Ag nanoparticles, and we show that it brings about uniform lithium deposition. The binding energy for Li is increased by the abundant oxygen sites and large surface area of the MOF, and concomitantly, the uniform distribution of Li nuclei can be achieved with a low nucleation overpotential. When highly conductive lithiophilic Ag is incorporated into the MOF, the binding energy for Li is further increased and the nucleation overpotential is decreased to nearly zero. As a result, Li platting and stripping on the Ag@MOF (i.e., Ag@HKUST-1) substrate exhibit a Coulombic efficiency of 97% over 300 cycles and a high areal capacity of 5 mA h cm without dendrite formation.
金属锂阳极的发展受到锂枝晶的阻碍，这些枝晶是由于锂金属在循环过程中随机沉积而产生的。因此，在重复循环中实现锂的均匀沉积对于开发金属锂电池至关重要。然而，由于电解液中的对流，很难调节锂的沉积。在这里，我们采用了由极性金属有机骨架（MOF）和高导电性 Ag 纳米粒子组成的双亲锂结构，并证明它可以实现均匀的锂沉积。MOF 丰富的氧位和大的比表面积增加了 Li 的结合能，同时可以用低形核过电势实现 Li 核的均匀分布。当高导电性亲锂的 Ag 掺入 MOF 时，Li 的结合能进一步增加，形核过电势降低到接近零。结果，在 Ag@MOF（即 Ag@HKUST-1）基底上进行 Li 的电镀和剥离，在 300 次循环中库仑效率达到 97%，面容量达到 5 mA h cm，没有枝晶形成。
