3D li-ion microbattery has gained an increasing importance since the development of microelectromechanical systems (MEMS). Compared with the limited areal capacity for thin-film microbattery, 3D microbattery has the advantage of fully utilizing the limited footprint area without sacrificing the power density. Most of the 3D microbatteries that have been published nowadays require the a) patterning and/or depositing process to define the 3D electrode’s architecture and b) sealing case to ensure the encapsulation for liquid electrolyte. These process increase the difficulty to manufacture 3D microbatteries.

UV-curable gel polymer electrolyte (GPE) is one of the routes for creating low-cost, high-yield 3D microbatteries. By using the micro-stereolithography system, GPE can be built into different 3D shapes. Poly (ethylene oxide) (PEO) has been used as the polymer host in the polymer electrolyte. By incorporating lithium salt and organic solvents as plasticizers into the PEO host, a stable and high-conductivity gel electrolyte can be formed. The GPE combines the mechanical properties of a swollen polymer network with the high ion conductivity of the liquid electrolyte.

Here we demonstrated a method to manufacture 3D gel polymer electrolyte for microbattery. We characterized the GPE membrane by Electrochemical Impedance Spectroscopy (EIS). The result shows a promising ionic conductivity for the use of solid-state li-ion battery. A half-cell has also been assembled for studying the GPE’s cycle performance. The GPE is then fabricated by stereolithography into different 3D structures. SEM picture shows a nano-porous structure in GPE which facilitates the ion transportation. Assembled with electrode material and current collector, the 3D GPE can be built into a 3D microbattery. The microbattery shows a successful operation for 2 cycles, with a capacity of 1.4mAh cm².