In-plane Defect Engineering Enabling Ultra-Stable Graphene Paper-based Hosts for Lithium Metal Anodes

Graphene papers are widely studied as stable hosts to suppress lithium dendrite growth and accommodate the volumetric expansion for lithium metal anodes. Designing and constructing flexible graphene-based films with unique structures as stable hosts in large scales for lithium metal anodes is challenging in terms of their realistic applications. Herein, scalable three-dimensional (3D) holey reduced graphene oxide (HrGO) films with abundant as-tailored oxygen functional groups on hole defects of graphene nanosheets are successfully constructed as stable hosts for lithium metal anodes. The as-designed anodes deliver a stable voltage of 11 mV for 1900 h at a current density of 0.2 mA cm(-2). The achieved cycling times of the optimized Li-HrGO-4 film anodes are over 1000 and 800 h at current densities of 0.5 and 1.0 mA cm(-2), respectively. Simultaneously, the Li-HrGO-4 composite film anodes also exhibit superior rate performance as compared to pure lithium and Li-rGO film anodes when utilized in symmetric cells. The as-assembled LiFePO4/Li-HrGO-4 full cells show superior rate performance and retain capacity after 300 cycles at the rate of 1 C. Furthermore, first-principles calculations indicate that C-O and O-C=O groups on defects of HrGO surfaces lead to excellent lithium affinity and uniform deposition. Above all, the unique 3D holey structure with as-tailored oxygen defects and its design strategy holds a significant potential for the development of high energy-dense and stable metal batteries.