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(～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.

Yangjun Mao;Xiao Chen;Hao Cheng;Yunhao Lu;Jian Xie;Tao Zhang;Jian Tu;Xiongwen Xu;Tiejun Zhu;Xinbing Zhao

State Key Laboratory of Silicon Materials,School of Materials Science and Engineering,Zhejiang University,Hangzhou 310027,China;Department of Physics,Zhejiang University,Hangzhou 310027,China;State Key Lab of High Performance Ceramics and Superfine Microstructure,Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai 200050,China;LI-FUN Technology Corporation Limited,Zhuzhou 412000,China

能源与环境材料（英文）

[1]Yangjun Mao;Xiao Chen;Hao Cheng;Yunhao Lu;Jian Xie;Tao Zhang;Jian Tu;Xiongwen Xu;Tiejun Zhu;Xinbing Zhao-.Forging Inspired Processing of Sodium-Fluorinated Graphene Composite as Dendrite-Free Anode for Long-Life Na-CO2 Cells)[J].能源与环境材料（英文）,2022(02):572-581

hammering

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