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.

For microelectronic devices, the on-chip microsupercapacitors with facile construction and high performance, are attracting researchers’ prior consideration due to their high compatibility with modern microsystems. Herein, we proposed interchanging interdigital Au-/MnO₂/polyethylene dioxythiophene stacked microsupercapacitor based on a microfabrication process followed by successive electrochemical deposition. The stacked configuration of two pseudocapacitive active microelectrodes meritoriously leads to an enhanced contact area between MnO₂ and the conductive and electroactive layer of polyethylene dioxythiophene, hence providing excellent electron transport and diffusion pathways of electrolyte ions, resulting in increased pseudocapacitance of MnO₂ and polyethylene dioxythiophene. The stacked quasi-solid-state microsupercapacitors delivered the maximum specific capacitance of 43 mF cm⁻² (211.9 F cm⁻³), an energy density of 3.8 μWh cm⁻² (at a voltage window of 0.8 V) and 5.1 μWh cm⁻² (at a voltage window of 1.0 V) with excellent rate capability (96.6% at 2 mA cm⁻²) and cycling performance of 85.3% retention of initial capacitance after 10000 consecutive cycles at a current density of 5 mA cm⁻², higher than those of ever reported polyethylene dioxythiophene and MnO₂-based planar microsupercapacitors. Benefiting from the favorable morphology, bilayer microsupercapacitor is utilized as a flexible humidity sensor with a response/relaxation time superior to those of some commercially available integrated microsensors. This strategy will be of significance in developing high-performance on-chip integrated microsupercapacitors/microsensors at low cost and environment-friendly routes.