Novel 3D grid porous Li₄Ti₅O₁₂ thick electrodes fabricated by 3D printing for high performance lithium-ion batteries

Three-dimensional (3D) grid porous electrodes introduce vertically aligned pores as a convenient path for the transport of lithium-ions (Li-ions), thereby reducing the total transport distance of Li-ions and improving the reaction kinetics. Although there have been other studies focusing on 3D electrodes fabricated by 3D printing, there still exists a gap between electrode design and their electrochemical performance. In this study, we try to bridge this gap through a comprehensive investigation on the effects of various electrode parameters including the electrode porosity, active material particle diameter, electrode electronic conductivity, electrode thickness, line width, and pore size on the electrochemical performance. Both numerical simulations and experimental investigations are conducted to systematically examine these effects. 3D grid porous Li₄Ti₅O₁₂ (LTO) thick electrodes are fabricated by low temperature direct writing technology and the electrodes with the thickness of 1085 μm and areal mass loading of 39.44 mg·cm^-2 are obtained. The electrodes display impressive electrochemical performance with the areal capacity of 5.88 mAh·cm^-2@1.0 C, areal energy density of 28.95 J·cm^-2@1.0 C, and areal power density of 8.04 mW·cm^-2@1.0 C. This study can provide design guidelines for obtaining 3D grid porous electrodes with superior electrochemical performance.