Abstract

Energy storage devices such as Electrochemical Double Layer Capacitors and other types of the electrochemical capacitors require chemically stable, non-soluble, electrochemically active electrode materials compatible with appropriate electrolytes. Factors which determine their applicability are derived from so called electrochemical window of electroltes, nature of charge accumulation and their kinetics. On the other hand technological aspects related to the electrode film formation or importance considering transference of experimental laboratory data into manufacture of the device scale. Therefore many attemps have been made towards formation of the hybrid systems comprising different type of compounds in systems formed to act as the electrodes in fast charging-discharging devieces. There are two main ways to combine in one electrode materials different counterparts: 1) the first conceps is aimed towards harvesting of electroactivity from components active at the same potential range, 2) in the second approach used components are electroactive at the different potential range (expanding E function) also synergy between their activity is expected. Both cases should bring about increase in electric energy storage, however in different way. In the first group of hybrid materials the example is organic/inorganic composite systems made of polymer and metal hexacyan0oferrates. The example of second type of hybrids is composite made on non metal doped titania combined with organic conducting film. Here a pseudofaradaic reaction at the TiO2 surface, active at hig anodic polarization is overlapping with pseudofaraic current of positively charged polymer. This composite works both in contact with aqueous and non-aqueous electrolytes. In non-aqueous electrolytes the benefit of the combined material is reached as the activity is observed from 3.8 V up to 0.7 V vs Li/Li+. Moreover titania is undergoing slower intercalation reaction. The usage of graphene in a composite should bring about improvement of electrode performance. However it is not the straightforward case for graphene implementation when ion-to-electron transducer is required for good electric connection between counterparts (PEDOT + TiO2)

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