On-Chip High-Power Supply Unit: Micro Supercapacitor With Superb Capacitance Density and Fast Charge/Discharge Ability

Abstract

Stable working voltage is critical for integrated systems to keep functioning, yet it suffered from instantaneous high-power demands and the resulting voltage disturbance. An on-chip micro supercapacitor (MSC) with superb capacitance density can act as a promising high-power supply unit to satisfy power demands and stabilize the system. However, severe capacitance decay of MSC under fast charge/discharge rate greatly weakens the device power output thus making it incompetent. This work demonstrates an on-chip high-power MSC featured by the improved capacitance density, fast charge/discharge ability and scaling-down capability. The improvement is brought by the applied mesoporous gold as electrode framework, which offers fast electronic/ionic pathway and reduces porous effect under high charge/discharge rate; as well as the uniform MnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> active layer, which is decorated by an electrochemical potential-modulated deposition method, providing large pseudocapacitance. Moreover, the asymmetric electrode structure is constructed to expand the single device operation voltage. As a result, a large steady capacitance density of 9 mF/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and small capacity loss of 28% at high scan rate of 1 V/s have been achieved, leading to an unprecedented power density of 138 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .