Dual Lithiophilic Structure for Uniform Li Deposition.

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-2 without dendrite formation.