Porous tantalum network structures exhibiting high electrochemical performance as capacitors

Abstract

Tantalum is a key material that is used to produce small solid capacitors with high volumetric efficiency. To achieve higher capacitances in a given volume, Ta nanopowders (NPs) with a large surface area are required for anode preparation. In this study, we report the synthesis of porous tantalum network structures by the combustion method and its electrochemical performance as a capacitor. The network structures, which consist of Ta NPs, are formed via a high-temperature sintering process. The Ta NPs were produced with a minimum size of less than 50 nm and a BET surface area of 31.47 m2/g. Additionally, the formation of Ta porous network structures according to the Ta/Mg ratio was theoretically analysed using a phase field sintering model. According to an analysis of the electrical properties of a sintered Ta anode (k=20), a capacitance of ~190,000 μFV/g is achieved with Ta NPs having a BET surface area of 19.2 cm2/g. In the near future, we hope to achieve ~300,000 μFV/g capacitance with 31.47 m2/g BET surface area Ta NPs.