Toward uniform Li plating/stripping by optimizing Li-ion transport and nucleation of engineered graphene aerogel

Great efforts have been made to optimize Li metal anodes to improve energy density and cycle life. However, challenges remain in achieving uniform Li plating/stripping while maintaining stable interphase chemistry. Here, an engineered graphene aerogel with uniformly oriented microscale channels, and normalized lithiophilic binding sites as hosted Li anodes is reported. Vertically aligned graphene with oriented channels are constructed using a freeze-drying mechanism, and highly lithiophilic binding sites are optimized by adjusting functional oxygen anions on graphene. Based on the in-situ optical microscopy visualization and first-principles calculations, this graphene host design presents homogeneous Li-ion nucleation owing to its straight transport channels with ultrahigh lithiophilicity, resulting in greatly improved cycling stability. Also, the flat and compatible electrode-electrolyte interphase facilitates smooth Li growth, thereby suppressing the formation of dendrites. Notably, the symmetric cells using the new composite anodes exhibit superior electrochemical reversibility over 500 cycles, with the patternable LiFePO4//Li@graphene pouch cells displaying outstanding cycling performance. This graphene-hosted Li anode thus demonstrates great potential for Li batteries.

Automated summary

The research introduces a new design of using graphene aerogel as the host for Li metal anodes, which achieves homogeneous Li-ion nucleation and improved cycling stability through optimized channel structures and lithiophilic binding sites. The results demonstrate the great potential of this graphene-hosted Li anode in terms of electrochemical performance and cycling life.