The photo is sourced from minobrnauki.gov.ru
The results of their research were published in Applied Sciences journal of the Multidisciplinary Digital Publications Institute (MDPI).
In fact, super condensers are facilities for short-term storage of energy. Their main advantage is high charging rate: for Li-ion batteries such rate is no less than 10 minutes, but for super condensers it varies from 1 to 10 seconds. Super condensers are capable of lasting for up to 1 mln of charge-discharge cycles, while as standard batteries – no more than 500 cycles. Thanks to quick regeneration of the accumulated energy, super condensers are used for smoothing the wind turbines power output, which may vary very much depending on the wind velocity.
Scientists from SPSU and Omsk research center with the Siberian branch of RAS proposed to improve the efficiency of super condensers by way of combining multilayer nanotubes and transition metals oxides. Nanotubes are carbonic cylindrical structures created from graphene (the crystalline lattice layer 300 thou times thinner than the paper sheet) and simultaneously featuring high density and durability. In general, there are two types of nanotubes: single-walled (with one-dimensional structure) and multilayered (consisting of several concentrically connected nanotubes), and the last-named ones are the best fit for making batteries and super condensers: due to both better conductivity of current, and chemical inertness of the surface preventing any reactions.
Manganese oxide is an example of the above mentioned transition metals oxides. It is dark-brown powder used in rechargeable batteries featuring high specific capacitance and low toxicity. Respectively, during the experiment the scientists put layers of manganese oxide on the nanotubes’ surface, and then the received composite material was subject to heat treatment for crystallisation and forming of nanoparticles. Finally, at the last stage, rhenium oxide was added (black-and-white water-insoluble crystals), which allowed for improving the electrochemical properties of the composite material.
“The received composite material demonstrated excellent capacity features, i.e., accumulated charge per one unit of mass, and this is one of the main parameters of such materials”, Pyotr Korusenko, the research associate from SPSU Department of Solid State Electronics says. – “The bigger charge can be accumulated by the composite material during short period of time and then give it away, the higher efficiency it features”.
The outcomes of this research can improve the efficiency of pulse power sources generating big amount of energy within short periods. In addition to the renewable energy sector, they may also be used in transportation systems and small energy storage devices.