Title: Next‐Generation Additive Manufacturing: Tailorable Graphene/Polylactic(acid) Filaments Allow the Fabrication of 3D Printable Porous Anodes for Utilisation within Lithium‐Ion Batteries

Abstract: Herein, we report the fabrication and application of Li‐ion anodes for utilisation within Li‐ion batteries, which are fabricated via additive manufacturing/3D printing (fused deposition modelling) using a bespoke graphene/polylactic acid (PLA) filament, where the graphene content can be readily tailored and controlled over the range 1–40 wt. %. We demonstrate that a graphene content of 20 wt. % exhibits sufficient conductivity and critically, effective 3D printability for the rapid manufacturing of 3D printed freestanding anodes (3DAs); simplifying the components of the Li‐ion battery negating the need for a copper current collector. The 3DAs are physicochemically and electrochemically characterised and possess sufficient conductivity for electrochemical studies. Critically, it is found that if the 3DAs are used in Li‐ion batteries the specific capacity is very poor but can be significantly improved through the use of a chemical pre‐treatment. Such treatment induces an increased porosity, which results in a 200‐fold increase (after anode stabilisation) of the specific capacity (ca. 500 mAh g⁻¹ at a current density of 40 mA g⁻¹). This work significantly enhances the field of additive manufacturing/3D printed graphene based energy storage devices demonstrating that useful 3D printable batteries can be realised.