Ice-Templated Free-Standing Reduced Graphene Oxide for Dendrite-Free Lithium Metal Batteries

Abstract

The Li metal is increasingly receiving attention as the ultimate anode material for Li metal batteries on account of its superior capacity and low redox potential. Recent studies have suggested that designing nanostructured hosts is an effective approach for resolving chronic issues of Li metal anodes, such as dendrite growth and dead Li generation. Nevertheless, the scalability of the nanostructured materials has been insufficiently recognized and discussed. Herein, we demonstrate a facile and scalable synthesis of free-standing reduced graphene oxide, utilizing the ice-templating method, and its application as a deposition host for the metallic Li. The synthesized graphene framework features a microchannel structure, which is propitious for accommodating large amounts of Li metal and stabilizing the solid electrolyte interphase layer. We fabricated the ice-templated graphene into a Li metal pouch cell and demonstrated an excellent coulombic efficiency of 97% for 200 cycles and a superior cycle life up to 980 h. Additionally, the Li-S full-cell delivered a high areal capacity of 8.5 mAh cm-2. Our results highlight that the microchannel graphene-based architecture is critical for minimizing the unrestricted growth of Li dendrites and alleviating the large volume changes. Furthermore, the scalable synthetic method provides an opportunity for employing Li metal at a practical level.