High power rechargeable batteries

Energy and power density are the key figures of merit for most electrochemical energy storage systems. Considerable efforts worldwide have been made to improve the energy density of rechargeable (secondary) batteries, as this is critical for most applications. As the penetration of batteries into ever more demanding applications has increased, power density, the allowed rate of energy transfer per unit volume or mass, is becoming equally important. High power density batteries have the potential to be rapidly charged, possibly in a few minutes or less, and can also deliver high peak discharge powers. Normally increases in power density are only possible through significant reductions in energy density, however emerging materials research is showing this needs not to be the case. Here we discuss emerging concepts in high power batteries, with a particular focus on Li-ion based chemistries.