Dendrite‐Free 3D Lithium Metal Anode Formed in a Cellulose Based Separator for Lithium‐Metal Batteries

Abstract Lithium metal is the best candidate anode for high specific energy density batteries because of its high specific capacity and low negative potential. However, lithium dendrite formation and growth during the lithium plating and stripping cycles have hindered the use of lithium metal as the anode for practical batteries. Here, a mechanism for the suppression of lithium dendrite formation and growth in a composite separator of Kimwipe paper (KW) and porous polyethylene (PE) for various electrolytes was examined. The Li/KW/PE electrode in an electrolyte of 1 m Li(CFSO 3 ) 2 N (LiFSI) in 1,4, dioxane (DX)‐1,2 dimethoylethane (DME) (1 : 2 v/v) with a wide electrochemical window was successfully cycled without lithium dendrite short‐circuiting at 5 mA cm −2 and 25 °C for 10 h over 25 cycles. Lithium was deposited into the cellulose fiber network during the lithium plating process, which resulted in the formation of a three‐dimensional (3D) lithium electrode. Whereas, the composite separator of KW and PE was not effective to suppress the lithium dendrite formation and growth with the conventional carbonate based electrolyte of 1 m LiPF 6 in ethylene carbonate‐dimethyl carbonate.