| Dec 13, 2013 |
Toward next-generation supercapacitors
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(Nanowerk News) Electric and hybrid vehicles may soon travel further without recharging their supercapacitor (SC) cell packs. Scientists investigated materials to increase the energy density of SCs, the main obstacle to their widespread use.
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Batteries and capacitors are both energy storage systems (ESSs). Batteries provide a slow and steady charge and discharge whereas capacitors rapidly charge and discharge. Conventional batteries are ill-suited to electric or hybrid cars. After running out of electricity (analogous to running out of petrol), recharging could take a couple of hours. With the advent of ultracapacitors or SCs, electric and hybrid cars seemed to find the solution to braking and accelerating, but SCs were too expensive and stored too little energy to replace batteries completely.
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Scientists initiated the EU-funded project 'New generation, high energy and power density supercapacitor based energy storage system' (HESCAP) to increase SC energy density and make them cost competitive with conventional batteries. Three types of electrode materials were evaluated consisting of nanoparticulate metal oxides, silica (silicon dioxide (SiO2), a metal oxide) coating on conventional carbon-based electrodes and activated carbon.
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Best results were obtained with activated carbons, particularly certain carbide-derived carbons (CDCs) that were used to design and optimise SC cells for prototyping. A rigorous experimental testing campaign together with simulations led to the optimisation of design specifications for integration into an SC stack. Scientists also carried out a full life-cycle assessment of the SC module to ensure an eco-design for a green ESS.
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HESCAP scientists made an important contribution to development of the experimental and theoretical knowledge base required to develop the next generation of SCs with higher energy density. Such development will be immediately applicable to the electric and hybrid vehicle market sector on the verge of an explosion with the appropriate enabling technologies.
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