A Laser‐Processed Carbon‐Titanium Carbide Heterostructure Electrode for High‐Frequency Micro‐Supercapacitors

Abstract Micro‐supercapacitors (MSCs) are an important energy storage component for future miniaturized electronic systems, yet their key performance indexes such as high‐frequency response, energy density, and cycle life still have a large room to be improved. Herein, a laser‐processed carbon‐titanium carbide heterostructure (LCTH) electrode is demonstrated, which can excellently address the above key challenges by employing a unique one‐step laser‐processing fabrication method. Different from the other reported electrode structures, this LCTH electrode shows a heterogeneous structure, featuring the carbon nanofoam layer which provides extremely short ion transport channels and abundant electrochemical active sites, and the underlying titanium carbide layer which can provide excellent electron conductivity and contribute to the pseudo‐capacitance. The assembled symmetric supercapacitor can stably work at the voltage window of 3.5 V at an ultra‐high frequency of approximately 1121.3 Hz, exhibiting an ultra‐high areal specific energy density of 721 µFV² cm⁻² at 120 Hz and a cycle life of 140 000 cycles with capacitance retention of 100.95%, which is superior to most reported MSCs. The as‐fabricated MSC is compatible with the contemporary embedded electronic component fabrication processes, which shows significant advantages in large‐scale fabrication and system integration, demonstrating a broad prospect for future system‐in‐package applications.