Advances in electrochemical energy storage technologies drive the need for battery safety performance and miniaturization, which calls for the easily processable polymer electrolytes suitable for on-chip microbattery technology. However, the low ionic conductivity of polymer electrolytes and poor-patternable capabilities hinder their application in microdevices. Herein, we modified SU-8, as the matrix material, by poly(ethylene oxide) (PEO) with lithium salts to obtain a patternable lithium-ion polymer electrolyte. Due to the highly amorphous state and more Li-ion transport pathways through blending effect and the increase in number of epoxides, the ionic conductivity of achieved sample is increased by an order of magnitude to 2.9 × 10⁻⁴ S·cm⁻¹ in comparison with the SU-8 sample at 50 °C. The modified SU-8 exhibits good thermal stability (> 150 °C), mechanical properties (elastic modulus of 1.52 GPa), as well as an electrochemical window of 4.3 V. Half-cell and microdevice were fabricated and tested to verify the possibility of the micro-sized on-chip battery. All of these results demonstrate a promising strategy for the integration of on-chip batteries with microelectronics.

Surface modification of graphene oxide (GO) is a powerful strategy to develop its energy density for electrochemical energy storage. However, pre-modified GO always exhibits unsatisfactory hydrophilia and its ink-relevant utilization is extremely limited. Although GO ink is widely utilized in fabricating micro energy storage devices via extrusion-based 3D-printing, simultaneously obtaining satisfactory hydrophilia and high energy density still remains a challenge. In this work, an in-situ surface engineering strategy was employed to enhance the performance of GO micro-supercapacitor chips. Three dimensionally printed GO micro-supercapacitor chips were treated with pyrrole monomer to achieve selective and spontaneous anchoring of polypyrrole on the microelectrodes without affecting interspaces between the finger electrodes. The interface-reinforced graphene scaffolds were edge-welded and exhibited a considerably improved specific capacitance, from 13.6 to 128.4 mF·cm⁻². These results are expected to provide a new method for improving the performance of micro-supercapacitors derived from GO inks and further strengthen the practicability of 3D printing techniques in fabricating energy storage devices.