Laser-processed micro/nano electrodes for integrated devices: Architectures, mechanisms and prospects

Ongoing miniaturization and integration of electronic devices are driving a growing demand for multifunctional and reliable micro/nano electrodes that enable microscale energy storage and harvesting. This review summarizes recent advances enabled by laser processing, an inherently maskless, precise, multi-dimensional (across one, two, and three dimensions), and designable toolkit for fabricating and enhancing micro/nano electrodes, with a focus on process–structure–property relationships, which are highly important for device and system-level implementation. Laser–material interactions are elucidated by distinguishing physical modifications from chemical transformations, and the connection between processing windows and the resulting architectures and properties is established. Laser processing plays a vital role in enhancing electrode performance, including higher specific surface area, faster ion transport, higher energy/power density, and enhanced reliability (robust cycling stability and strong substrate adhesion). Emphasis is placed on energy storage applications, including on-chip and high-energy-density micro-supercapacitors, where these miniaturized electrodes enable exceptional capacitance and electrical conductivity. Beyond energy storage, broader prospects such as multifunctional electrodes that simultaneously serve as energy storage and sensing components in compact heterointegrated devices are attracting research interest. Emerging ultrafast laser processing and combinational fabrication techniques, coupled with multifunctional hierarchical designs, are considered as effective routes toward micro/nano electrodes with higher performance and integration levels, opening avenues for next-generation integrated devices.