A hierarchical SiO2-microsphere-graphene host enabling superior long-term cycling for lithium-metal anodes.

Metallic lithium (Li) is considered to be one of the most promising anodes for Li-ion batteries due to its high theoretical capacity and low reduction potential. However, dendritic growth and substantial volume variations during battery operation make it difficult for commercialization. Here, a graphene and SiO 2 composites material was presented as a lithiophilic host to enable superior long-term cycling for Li-metal anode. The porous skeleton of graphene with excellent electronic conductivity can effectively reduce the actual current density and suppress the volume expansion. And the SiO 2 particles with excellent ionic conductivity can significantly suppress the growth of Li dendrites and regulate the nucleation sites. So doping SiO 2 nanoparticles between graphene sheets can significantly suppress the growth of Li dendrites and the volume expansion effect of metallic Li deposition, while also providing good electrochemical performance. Benefitting from these synergistic effects, the Li-GF@SiO 2 battery exhibits excellent electrochemical reversibility over 500 cycles depositing 1 mAh cm−2 of metallic Li at a current density of 1 mA cm−2, and the coulombic efficiency of the Li-GF@SiO 2 battery is still as high as 97%, but the Li-Cu battery decays after 75 cycles. So this hierarchical SiO 2 -microsphere-graphene host demonstrates great potential for Li batteries. • The type of graphene and SiO 2 composite material is designed for the stable host of lithium (Li) metal anode because of its lithiophilic character. • The hierarchical silica spheres can effectively reduce the actual current density and guide the nucleation of Li metal. • The superior electronic conductivity and ionic conductivity of composite materials are utilized to suppress the growth of Li dendrites and volume expansion. • The novelty lithiophilic host of Li metal anode can achieve over 500 cycles at a current density of 1 mA cm−2 for Li-metal batteries. [ABSTRACT FROM AUTHOR]