A Scalable Approach to Dendrite-Free Lithium Anodes via Spontaneous Reduction of Spray-Coated Graphene Oxide Layers.

Li-metal batteries (LiMBs) are experiencing a renaissance; however, achieving scalable production of dendrite-free Li anodes for practical application is still a formidable challenge. Herein, a facile and universal method is developed to directly reduce graphene oxide (GO) using alkali metals (e.g., Li, Na, and K) in moderate conditions. Based on this innovation, a spontaneously reduced graphene coating can be designed and modulated on a Li surface (SR-G-Li). The symmetrical SR-G-Li|SR-G-Li cell can run up to 1000 cycles at a high practical current density of 5 mA cm-2 without a short circuit, demonstrating one of the longest lifespans reported with LiPF6 -based carbonate electrolytes. More significantly, a practically scalable paradigm is established to fabricate dendrite-free Li anodes by spraying a GO layer on the Li anode surface for large-scale production of LiFePO4 /Li pouch cells, reflected by the continuous manufacturing of the SR-G-Li anodes based on the roll-to-roll technology. The strategy provides new commercial opportunities to both LiMBs and graphene.