Synergetic control of heterogeneous nucleation and 3D mixed electron/ ion-conducting paths for dendrite-free Li metal anodes

A 3D mixed electron/ion-conducting Ag-Li2Se@CFC scaffold was successfully fabricated through the in-situ conversion reactions between Ag2Se-coated carbon fiber clothes (Ag2Se@CFC) and molten Li to form fast Li+ ion-conducting Li2Se and electron-conducting Ag in the carbon fiber clothes during the molten Li impregnation process. Moreover, the in-situ formed Ag nanoparticles in the Ag-Li2Se@CFC scaffolds have superior lithiophilic nature and act as heterogeneous nucleation nanoseeds for Li deposition, thus inducing the uniform behaviors of Li plating and stripping. Due to the synergetic control of heterogeneous nucleation and the 3D mixed electron/ ion-conducting paths of the Ag-Li2Se@CFC scaffolds, the resulted Ag-Li2Se@CFC/Li composite anodes could effectively prohibit the Li dendrite growth, demonstrating excellent long-term cycling stability of Li plating/ stripping in symmetric cells with extremely low overpotentials of 3 mV at 1 mA cm-2 over 1000 cycles. Furthermore, when coupled with LiFePO4, LiNi0.8Co0.1Mn0.1O2 or sulfur/carbon composite cathodes to assemble coin-typed full cells for potential applications, the Ag-Li2Se@CFC/Li composite anodes still deliver improved cycling stabilities and rate performances. These encouraging results suggest the synergetic control of heteroge-neous nucleation and 3D mixed electron/ion-conducting scaffolds should be a promising strategy for achieving dendrite-free Li metal anodes.