Miniature power sources are needed for a variety of applications, including implantable medical devices, remote microsensors and transmitters, “smart” cards, and Internet of things (IoT) systems. Today's rechargeable lithium-ion batteries - with the best performance on the subject of energy density and with a reasonably good power efficiency - dominate the consumer market. Insufficient areal energy density from thin-film planar microbatteries has inspired a search for three-dimensional microbatteries (3DMB) with the use of low cost and efficient micro- and nano-scale materials and techniques. The exclusive capabilities of the 3D-printing technology enable the design of different shapes and high-surface-area structures, which no other manufacturing method can easily do. We present a novel, quasi-solid rechargeable 3D microbattery assembled on a 3D-printed perforated polymer substrate (3DPS) with interconnected channels formed through XYZ planes. Simple and inexpensive electrophoretic-deposition routes are applied for the fabrication of all the thin-film active-material layers of the microbattery. With the advantage of thin films, which conformally follow all the contours of the 3D substrate and are composed of nanosize electrode materials, like modified Lithium Iron Phosphate (LFP, Lithium Titanate (LTO), and original polymer-in-ceramic electrolyte, our 3D microbatteries offer high reversible specific capacity and high pulse-power capability.