▎ 摘　　要

Na-CO2 batteries recently are emerging as promising energy-storage devices due to the abundance of Na in the earth's crust and the clean utilization of greenhouse gas CO2. However, similar to metallic Li, metallic Na also suffers from a serious issue of dendrite growth upon repeated cycling, while a facile method to solve this issue is still lacking. In this work, we report an effective, environmentally friendly method to inhibit Na dendrite growth by in situ constructing a stable, NaF-rich solid electrolyte interface (SEI) layer on metallic Na via adding a small amount (similar to 3 wt%) of fluorinated graphene (FG) in bulk Na. Inspired by the forging processing, a uniform Na/FG composite was obtained by melting and repetitive FG-adsorbing/hammering processes. The Na/FG-Na/FG half cell exhibits a low voltage hysteresis of 110-140 mV over 700 h at a current density up to 5 mA cm(-2) with an areal capacity as high as 5 mAh cm(-2). Na-CO2 full cell with the Na/FG anode is able to sustain a stable cycling of 391 cycles at a limited capacity of 1000 mAh g(-1). Long cycle life of the cell can be attributed to the protecting effect of the in situ fabricated NaF-rich SEI layer on metallic Na. Both experiments and density functional theory (DFT) calculations confirm the formation of the NaF-rich SEI layer. The inhibition effect of the NaF-rich SEI layer for Na dendrites is verified by in situ optical microscopy observations.