Fabrication of Laser-induced Microsupercapacitors for structurally-integrated power storage systems

Abstract

The rapidly growing demand for highly integrated, wearable, portable as well as implantable electronics such as wireless autonomous sensors, health monitoring devices etc. has significantly stimulated the need for miniature energy storage devices for constant power supply [1,2]. Similarly, the future aerospace and aircraft systems are also looking for clean and decentralized power supply for various quality, safety and system monitoring requirements. Till date, thin film batteries or micro-batteries have been considered as promising energy supplier [3,4]. However, safety concern, low power and limited lifetime of these batteries prevent their widespread application. Recently, micro-supercapacitors (MSCs) have attracted enormous attention as a promising flexible on-chip and microscale energy storage devices owing to their several excellent properties such as fast charge/discharge capability, high power density, ultrahigh life cycle, light weight and easy maintenance [5]. On the other hand, electrolytes as a component of a supercapacitor play a crucial role for energy storage performance. Among various types of electrolytes, solid/gel polymer electrolytes are very useful for fabrication of MSCs due to high ionic conductivity, leakage free, interfacial compatibility, good flexibility and nonflammability [6,7]. This research work targets to emphasize the fabrication of lase induced Graphene (LIG)-based EDLC electrodes at ambient temperature for use in flexible and scalable micro-supercapacitor. An optimized ion transport pathway is aimed to achieve via the enhanced electrode porosity resulting in a wider potential window. In this context, we report the optimization and fabrication of MSCs based on laser-induced interdigital structured graphene electrodes fabricated by CO2-laser structuring of polyimide-based Kapton foils. For scanning the Kapton foil, a continuous wave (CW) CO2-Laser engraving machine with λ = 10.6 µm applied in order to obtain the geometry shown in Figure 1. The dimension of such fabricated MSC-devices was 24 × 10.5 mm. The interdigital Graphene electrodes displayed a hair comb formation which had 12 branches of 7.5 × 0.8 mm equally distributed on each bar of the comb. The SEM image (Figure 2a) shows the morphology of the LIG converted of from PI-foils with a laser power of 6 W and the XRD of this LIG-combs is given in Figure 2b. References: [1] P. Zhang et al. Energy Storage Materials 28 (2020) 160–187. [2] L. Zhang et al. Energy Storage Materials 32 (2020) 402–417. [3] J. Zhang et al. Adv. Funct. Mater. 2020, 30, 1910000. [4] C. Zhao et al. Adv. Mater. Technol. 2018, 3, 1800028 [5] F. Bu et al. npj Flexible Electronics (2020) 31. [6] J. Wang et al. Small Methods 2019, 3, 1800367. [7] A. Ray, J. Roth, B. Saruhan, Molecules, 27(2022), 329.