3D Printed TiO₂ Negative Electrodes for Sodium-Ion and Lithium-Ion Batteries Using Vat Photopolymerization

Additive manufacturing represents a unique approach to develop three-dimensional shape-conformable batteries with enhanced surface area, ion diffusion, and power. For the first time, a composite photocurable resin loaded with solid particles of active materials and conductive additives was prepared and used as feedstock to print negative electrodes for sodium-ion and lithium-ion batteries by means of a vat photopolymerization (VPP) 3D printer. In alignment with NASA’s Artemis mission goals to develop sustainable lunar energy storage infrastructure to support long-term human operations, TiO₂ was selected as an active material for the negative electrode due to its abundance on the lunar surface. The TiO₂ loading in the composite photocurable resin was increased as high as possible to maximize the electrochemical performance of the printed electrodes, while simultaneously ensuring printability and good mechanical strength for sample handling. The effect of thermal post-processing on the electrical, electrochemical, and mechanical performance is reported. A configurational study is implemented to identify the impact of electrode designs (cubic and gyroid) on the electrochemical performance. This work addresses the difficulties related to the introduction of solid particles within a photocurable resin and the need for a compromise between the electrochemical performances and printability to obtain fully functional VPP-printed electrodes.