Hybrid Composite Electrodes for Supercapasitors Prepared By Simple Routes

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Supercapacitors, which can store energy by a combination of electrostatic (double layer capacitance) and electrochemical (pseudocapacitance) storage of electrical energy, are an important energy storage device applicable for a variety of uses and technologies, especially in applications which requires rapid charge/discharge cycles and several thousands of cycles, e.g. short term energy storage and high power delivery. The asymmetric electrode configuration which allows for the use of aqueous electrolytes are a promising route to low-cost and environmentally friendly supercapacitors without compromising power and energy density. Here we present a novel approach based on easy synthesis methods to prepare hybrid electrode materials consisting of mixed transition metal oxides for the redox contribution together with carbonaceous materials contributing to the double layer response. The synthesis methods used are possible to scale up and results in nanosized, high surface area hybrid electrode materials. Three different methods have been selected resulting in significant different morphologies and characteristics. The electrode materials have been characterized by standard physical techniques, e.g. SEM, TEM, EDX and XRD. To prepare final electrode materials, inks using PTFE, ketjen black and H2O/isopropanol, was spray coated on carbon paper with a loading of approximately 1 mg/cm2. The electrodes were tested for electrochemical performance as capacitors, by use of techniques such as cyclic voltammetry and charge and discharge curves, as a function of electrode composition, time and type of aqueous based electrolyte, and compared with hybrid electrodes fabricated by e.g. electrodeposition methods.Preliminary results have shown that it is possible to produced hybrid materials through cheap and flexible processes in aqueous electrolytes.