Janus-structured graphene scaffold for bottom-up lithium deposition: A progressive gradient approach

Graphene-based materials have been explored as hosts for Li metal anodes, but their high interfacial activity and short diffusion distances frequently result in dendrite formation on the surface. Herein, we utilize the adjustable conductivity and Li affinity of graphene oxide (GO) to develop a Janus structure comprising a top GO layer and a bottom reduced graphene oxide (rGO) layer. The progressive conductivity and lithiophilicity gradient structure of GO/rGO enables a bottom-up Li deposition mode, rendering an average Coulombic efficiency of 99.1 % over 350 cycles at 1 mA cm⁻² and 1 mAh cm⁻². Full cells equipped with a LiFePO₄ cathode maintain a capacity retention of 85 % after 350 cycles at 1 C. This innovative approach provides fresh insights into the development of graphene-based hosts, offering significant potential for future Li metal battery applications.