Improved design of highly efficient microsized lithium-ion batteries for stretchable electronics

Abstract

We introduce a stretchable microsized Li-ion battery with a novel design. The battery was fabricated using a facile technique and exhibited high performance. Dry-etching process was utilized to pattern lithium phosphorus oxynitride for avoiding the use of a photoresist developer (photolithography), which can damage the amorphous lithium manganese oxide (LiMn2O4 (LMO)) cathode. This allowed us to fabricate the current collectors and electrodes away from the main body of the microsized battery (a parallel structure rather than a stacked, i.e. perpendicular structure). An enhanced capacity of similar to 150 mAh g(-1) was achieved using the parallel device structure at a charge-discharge average potential of 3.7 V; in comparison, the performance of a device with a stacked structure was significantly inferior. The microsized batteries were utilized to illuminate a white inorganic light-emitting diode with a turn-on voltage of similar to 2.5 V. The fabricated devices with the stacked structure were transferred to a mechanically prestrained (similar to 22.5%) polydimethylsiloxane polymer via a kinetic transfer process. Upon removal of the prestrain, the shrinkage of the substrate caused buckle formation at the interconnects, and tensile damage to the microsized batteries was circumvented. The simulation (COMSOL) results indicated that most of the strain in the standby form (without applied stretching) was concentrated at the interconnects, preventing significant damage in the main device area. Upon the application of 21% stretching (load), although the parallel structure exhibits slightly higher maximum strain in the islands, the strain distribution was more effectively managed, indicating the potential of the proposed method for various stretchable and bendable optoelectronic applications.