Three-dimensional high-aspect-ratio microarray thick electrodes for high-rate hybrid supercapacitors

Hybrid supercapacitors (HSCs) with facile integration and high process compatibility are considered ideal power sources for portable consumer electronics. However, as a crucial component for storing energy, traditional thin-film electrodes exhibit low energy density . Although increasing the thickness of thin films can enhance the energy density of the electrodes, it gives rise to issues such as poor mechanical stability and long electron/ion transport pathways. Constructing a stable three-dimensional (3D) ordered thick electrode is considered the key to addressing the aforementioned contradictions. In this work, a manufacturing process combining lithography and chemical deposition techniques is developed to produce large-area and high-aspect-ratio 3D nickel ordered cylindrical array (NiOCA) current collectors. Positive electrodes loaded with nickel–cobalt bimetallic hydroxide (NiOCA/NiCo-LDH) are constructed by electrodeposition , and HSCs are assembled with NiOCA/nitrogen-doped porous carbon (NiOCA/NPC) as negative electrodes. The HSCs exhibits 55% capacity retention with the current density ranging from 2 to 50 mA cm −2 . Moreover, it maintains 98.2% of the initial capacity after long-term cycling of 15,000 cycles at a current density of 10 mA cm −2 . The manufacturing process demonstrates customizability and favorable repeatability. It is anticipated to provide innovative concepts for the large-scale production of 3D microarray thick electrodes for high-performance energy storage system.