One of the means that electrically powered vehicles used to maximize their range is regenerative braking where the kinetic energy of the vehicle is recaptured during deceleration and than released during acceleration. The problem is that most batteries can't absorb energy quickly enough to capture all the available energy. This is where capacitors have an advantage since they can absorb energy a lot faster than batteries and do it a lot more times. Unfortunately the total energy capacity is limited, which also limits their usefulness. While a lithium ion battery pack could contain enough energy to drive a vehicle a couple of hundred miles, an ultra-capacitor pack would be lucky to get a few miles.
Now a team of physicists at North Carolina State University have developed a new capacitor material that can contain up to seven times as much energy as existing capacitors. Vivek Ranjan, Liping Yu, Marco Buongiorno Nardelli and Jerry Bernholc figured adding a polymer called CTFE as an impurity to another polymer, polyvinylidene fluoride (PVDF) make for a much better capacitor dielectric greatly enhanced the latter's energy absorption. Perhaps if the cost of this material can be reduced a capacitor of this type could be combined with a battery to produce an energy system that can absorb and release energy quickly and still provide decent range.