Silicon-Based 3D All-Solid-State Micro-Supercapacitor with Superior Performance

The large-scale fabrication of high-performance on-chip micro-supercapacitors (MSCs) is the footstone for the development of next-generation miniaturized electronic devices. In practical applications, however, MSCs may suffer from a low areal energy density as well as a complicated fabrication strategy that is incompatible with semiconductor processing technology. Herein, we propose a scalable fabrication strategy for the realization of a silicon-based three-dimensional (3D) all-solid-state MSC via the combination of semiconductor-based electrode processing, chemical vapor deposition, and hydrothermal growth. The individual Si/C/MnO₂ electrode shows a maximum specific capacitance of 223.74 mF cm^-2, while the symmetric electrodes present a maximum areal energy density of 5.01 μWh cm^-2 at the scan rate of 1 mV s^-1. The full 3D Si/C/MnO₂ MSC delivers a high energy density of 2.62 μWh cm^-2, at a power density of 117.82 μW cm^-2, as well as a long cycle life with capacitance retention >92% after 4000 cycles. Our proposed method enables the fabrication of 3D MSCs based on a thick silicon interdigitated electrode array, holding a great promise for the development of 3D on-chip microscale energy storage devices.