In Situ Inorganic/Organic Protective Layer on Carbon Paper as Advanced Current Collector for Robust Li Metal Anode

Abstract Lithium (Li) metal is regarded as the most promising anode for next‐generation batteries with high energy density. However, the uncontrolled dendrite growth and infinite volume expansion during cycling seriously hinder the application of Li metal batteries (LMBs). Herein, an inorganic/organic protective layer (labeled as BPH), composed of in situ formed inorganic constituents and PVDF‐HFP, is designed on the 3D carbon paper (CP) surface by hot‐dipping method. The BPH layer can effectively improve the mechanical strength and ionic conductivity of the SEI layer, which is beneficial to expedite the Li‐ion transfer of the entire framework and achieve stable Li plating/stripping behavior. As a result, the modified 3D CP (BPH‐CP) exhibits an ultrahigh average Coulombic efficiency (CE) of ≈99.7% over 400 cycles. Further, the Li||LiFePO ₄ (LFP) cell exhibits an extremely long‐term cycle life of over 3000 cycles at 5 C. Importantly, the full cell with high mass loading LiFePO ₄ (20 mg cm ⁻² ) or LiNi _0.8 Co _0.1 Mn _0.1 O ₂ (NCM, 16 mg cm ⁻² ) cathode exhibits stable cycling for 100 or 150 cycles at 0.5 C with high‐capacity retention of 86.5% or 82.0% even at extremely low N/P ratio of 0.88 or 0.94. believe that this work enlightens a simple and effective strategy for the application of high‐energy‐density and high‐rate‐C LMBs.