A High-Performance Supercapacitor/Battery Hybrid Incorporating Templated Mesoporous Electrodes

A supercapacitor/battery hybrid was fabricated using a mesoporous positive electrode and a mesoporous Pd negative electrode, both fabricated by electrodeposition of the metal within the hexagonal phase of a liquid crystalline template. Because we are predominantly interested in the performance of the electrode, we have designed the device such that performance is positive electrode limited. Use of rather than NiO allows us to derive a significant proportion of the capacity from bulk redox processes and the designed porous electrode structure allows us to access this capacity very rapidly. Cyclic voltammetry and potential step experiments show that we are able to deliver or (of Ni electrode) in 50 ms at a mean discharge voltage of 1.18 V using an aqueous electrolyte. This translates into energy and power densities of and respectively, for the electrode. Furthermore, device capacity has been shown to resist decay and actually increase by 10% over 15,000 cycles. © 2003 The Electrochemical Society. All rights reserved.