Micro-supercapacitors are a promising alternative to micro-batteries because of their high power and long lifetime. They have been in development for about a decade but until now they have stored considerably less energy than micro-batteries, which has limited their application. Now researchers in the Laboratoire d’analyse et d’architecture des systèmes (LAAS-CNRS)1 in Toulouse and the INRS2 in Quebec have developed an electrode material that means electrochemical capacitors produce results similar to batteries, yet retain their particular advantages
They have developed an electrode material whose energy density exceeds all the systems available to date. The electrode is made of an extremely porous gold structure into which ruthenium oxide has been inserted. It is synthesized using an electrochemical process. These expensive materials can be used here because the components are tiny: of the order of square millimeters. This electrode was used to make a micro-supercapacitor with energy density 0.5 J/cm², which is about 1000 times greater than existing micro-supercapacitors, and very similar to the density characteristics of current Li-ion micro-batteries.
With this new energy density, their long lifetime, high power and tolerance to temperature variations, these micro-supercapacitors could finally be used in wearable, intelligent, on-board microsystems.