Dendrite‐Free Lithium Deposition and Stripping Regulated by Aligned Microchannels for Stable Lithium Metal Batteries

Abstract

Abstract Li metal is the ultimate choice for the anode in next‐generation high energy density rechargeable batteries. However, undesired dendrite growth, dead Li formation, and a large volume change of the lithium metal anode lead to severe safety hazards such as short‐circuiting, fire, or even explosion. Graphene oxide (GO) in large areas has been prepared as the Li metal host via a continuous centrifugal casting method. Aligned microchannels are then fabricated in it by a simple punching method using 3D printed templates. The GO matrix effectively regulates the lithium plating/stripping behavior while the aligned channels uniformly distributes the Li‐ion flux and provides short Li‐ion diffusion paths. The Li/ holey GO composite is flexible with a controllable thickness from 50 to 150 µm, which corresponds to capacities from 9.881 to 27.601 mAh cm −2 . As a result, the anode has a low overpotential of 30 mV after 100 h, a high capacity of ≈3538 mAh g −1 (91.4% of the theoretical capacity), and a superior rate ability of up to 50 C with a LiFePO 4 cathode. The holey GO/Li electrode is also paired with other cathodes and used in pouch cells, indicating its suitability for various high‐energy battery systems.