High energy density MIM-type aluminum electrolytic capacitors based on sintered aluminum powder anodes

Building high-energy density metal-insulator-metal type aluminum electrolytic capacitors (MIM-AECs) will open up new chapters for high-energy pulsed applications. Here, a high-energy density MIM-AECs were fabricated based on additively manufactured aluminum powder (Al-P) anodes. Due to the larger specific surface area of Al-P, the capacity density is increased by 11 % compared to conventional etched Al anodes. Meanwhile, a SnO₂/AlPO₄/AAO interface increases the Sn diffusion barrier and inhibits its diffusion into AAO, ensuring a high breakdown field strength (5.4 MV/cm). Moreover, the interface reduces carrier mobility and mitigates carrier acceleration, preventing local breakdown in device. Consequently, an exciting voltage (380 V) far exceeding that of conventional solid-state AECs capacitors is obtained, while an energy density (11.6 µWh/cm²) is ten times higher than that of reported MIM nanocapacitors. Strikingly, the capacitors exhibit a wide temperature window (-60 °C∼332 °C), strong humidity resistance (100 % RH) and high frequency response (300 kHz), far superior to commercial AECs.