A Combined Li Intercalation and Plating Mechanism Using Conductive Carbon Fiber Electrodes

Abstract

Lithium metal anodes (LMAs) are desirable for next-generation rechargeable batteries because of their high energy density. However, in practical applications they are hindered by inhomogeneous and uncontrolled Li dendrite deposition during cycling. Herein, we propose a dual charge storage mechanism, using freestanding carbon fiber paper (CFP) with carbon fillers electrode. These CFP electrodes are manufactured at an industrial scale and act both as a host for Li intercalation and as a conductive, porous, and lithiophilic 3D scaffold for Li plating/stripping. The CFP electrode exhibits excellent long-term cycling stability, as evidenced by Coulombic Efficiencies of over 99.5% on the 250th cycle in CFP|Li half-cells with a lithiation capacity of 1.5 mA h cm-2 and current density of 0.5 mA cm-2. We also demonstrate that the CFPs are sufficiently electrically conductive to operate in small pouch cells without metal foil current collectors, further improving the energy density of the proposed electrodes.