Preparation of Asymmetric Micro-Supercapacitors Based on Laser-Induced Graphene with Regulated Hydrophobicity and Hydrophilicity

Asymmetric micro-supercapacitors (AMSCs) with a small size and high energy density can be compatible with portable and wearable electronic devices and are capable of providing stable, long-term power supply, attracting great research interest in recent years. Here, we present a simple and rapid preparation method for AMSCs’ fabrication. By regulating the hydrophilicity and hydrophobicity of coplanar laser-induced graphene (LIG) through the adjustment of the laser parameters, two electrode materials with distinct hydrophilic–hydrophobic properties were selectively deposited by sequentially dip-coating. The LIGs serve as current collectors, with activated carbon and poly (3,4-ethylenedioxythiophene): poly (styrene sulfonate) as active materials. After coating the electrolytes and folding the two electrodes, a high-performance AMSC was achieved. The device exhibits a high areal capacitance of 85.88 mF cm⁻² at a current density of 0.4 mA cm⁻², along with an impressive energy density of 11.93 µWh cm⁻² and a good rate performance. Moreover, it is demonstrated to be highly stable in 500,000 cycles. Two AMSCs in series can supply power to an electronic clock and birthday card. The method of preparing asymmetric electrodes in the same plane greatly facilitates the large-area preparation of AMSCs and series–parallel connection, providing an excellent idea for developing high-performance miniature energy storage devices.