For achieving high energy density, one effective way is to increase the active materials which makes thick electrodes for Lithium-ion Batteries (LIBs). However, thickening electrode limits the charge transport and generates significant mechanical stress that results in poor performance and eventually failure. In this work, a novel micro-casting (µ-casting) process has been introduced to fabricate ultra-thick and 3D structured electrodes which can address the issues with low charge transport by establishing short diffusion path (SDP). SDP reduces the intercalation-induced stress, improves energy density and long-term stability. The µ-casting allows ultra-thick (~280 µm) cathode (NMC 811, LiNi_0.8Mn_0.1Co_0.1O₂) and anode (MCMB, MesoCarbon MicroBeads) to achieve 40% higher specific capacity and 30% higher areal capacity after 200 cycles, high C-rate performance and longer cycle life with a intensive high mass loading of 35.7 mg/cm².