Cell voltage versus electrode potential range in aqueous supercapacitors
نویسندگان
چکیده
Supercapacitors with aqueous electrolytes and nanostructured composite electrodes are attractive because of their high charging-discharging speed, long cycle life, low environmental impact and wide commercial affordability. However, the energy capacity of aqueous supercapacitors is limited by the electrochemical window of water. In this paper, a recently reported engineering strategy is further developed and demonstrated to correlate the maximum charging voltage of a supercapacitor with the capacitive potential ranges and the capacitance ratio of the two electrodes. Beyond the maximum charging voltage, a supercapacitor may still operate, but at the expense of a reduced cycle life. In addition, it is shown that the supercapacitor performance is strongly affected by the initial and zero charge potentials of the electrodes. Further, the differences are highlighted and elaborated between freshly prepared, aged under open circuit conditions, and cycled electrodes of composites of conducting polymers and carbon nanotubes. The first voltammetric charging-discharging cycle has an electrode conditioning effect to change the electrodes from their initial potentials to the potential of zero voltage, and reduce the irreversibility.
منابع مشابه
Numerical Analysis of Electric Double Layer Capacitors with Mesoporous Electrodes: Effects of Electrode and Electrolyte Properties
A theoretical study is presented of the behavior of electric double layer (EDL) supercapacitors constructed from mesoporous activated carbon electrodes. A threedimensional (3D) computational model is developed to predict the equilibrium charge distribution within the supercapacitor as a function of key electrode and electrolyte properties. The model is based on the modified Poisson− Boltzmann (...
متن کاملDifferent Supercapacitive Behavior of Two Glucose-derived Microporous Carbons: Direct Pyrolysis versus Hydrothermal Carbonization
This work compares for the first time the physical and chemical characteristics of activated carbons produced from glucose and hydrothermally carbonized glucose, as well as their performance as electrodes in supercapacitors in aqueous electrolyte (H2SO4). Both KOH-activated carbons exhibit similar textural properties, with BET surface areas of ~ 1400-1500 m/g and a pore volume of ~ 0.70 cm/g, t...
متن کاملSignificant Performance Enhancement in Asymmetric Supercapacitors based on Metal Oxides, Carbon nanotubes and Neutral Aqueous Electrolyte
Amongst the materials being investigated for supercapacitor electrodes, carbon based materials are most investigated. However, pure carbon materials suffer from inherent physical processes which limit the maximum specific energy and power that can be achieved in an energy storage device. Therefore, use of carbon-based composites with suitable nano-materials is attaining prominence. The synergis...
متن کاملEffects of different electrolytes on the electrochemical and dynamic behavior of electric double layer capacitors based on a porous silicon carbide electrode.
Controlling the structure and morphology of porous electrode materials is an effective strategy for realizing a high surface area and efficient paths for ion diffusion. Moreover, excellent electrical conductivity can significantly decrease the internal resistance of an electrode by the formation of a conductive network and facilitate the application of electrostatic charges, which favors the ac...
متن کاملEnhanced life-cycle supercapacitors by thermal treatment of mesophase-derived activated carbons
This paper studies the effect of thermal treatment on the long-term performance of carbon-based supercapacitors. Two active electrode materials were studied: a mesophase derived activated carbon (AC), rich in oxygen functionalities, and an activated carbon obtained from treating AC at 1000 °C (AC-1000), from which most of the functionalities had been removed. Up to 10,000 cycles were performed ...
متن کامل