Three-dimensional (3D) electrode structures have the potential to significantly improve Li-ion battery performance, including power and energy density. Due to the complexity of geometries caused by scale expansion, however, a more precise understanding of the relationship between battery physics and structures is required. In this work, a novel hybrid 3D structure is investigated to thoroughly understand the advantages of 3D structured electrodes and to provide a guideline for design optimization. Experimental observation from an extrusion-based 3D structure is incorporated into a 3D electrochemical model, based on porous theory, with a 4th order approximation for solid phase concentration. This systematic study has been focused on the impact of electrode tap density (thickness and volume fractions) on 3D battery performance. Experimental and simulation results showed that the proposed 3D hybrid structure exhibited higher specific capacity and areal capacity than conventional electrode structures. This was found to be due to the short diffusion path and uniformly distributed concentration within the electrodes, even with thicker electrodes. Parametric metrics were introduced to provide a physical insight into the 3D hybrid structure, to identify the factors limiting battery responses, and to, eventually, provide a guideline for design optimization with more general 3D geometries.