Abstract
At present, due to the development of portable device and electric vehicles, high energy density isn’t the only purpose required. Possessing high power density is another issue which needs to be considered. An electrical device containing both high energy density and high power density will be the most wanted result. As a result, a lithium ion capacitor has been designed by using pre-lithiated germanium/copper and silicon/copper nanowire fabric for negative electrodes with activated carbon for positive electrodes. For germanium, the performance is 200 F g-1 at 0.1 A g-1. And at high current density of 100 A g-1, the capacitance can still hold about 50 F g-1. The LIC have 108 W kg-1, when the energy density is 180 W h kg-1. While low energy density, the LIC would have ultrahigh power density of 110kW kg-1. For silicon, the performance of this LIC at 0.1 g-1 is 220 F g-1, which is approximated twice of capacitance of AC in EDLCs. Even at high current density of 50 A g-1, the capacitance can still hold about 80 F g-1. At a low power density of 170 W kg-1, the energy density is as high as 208 W h kg-1. The power density increases to 75 kW kg-1, which is much higher than most results in lithium ion capacitors, while the energy density still remains at 43 W h kg-1. As a result, we believe that this device can be used in numerous applications such as electrical vehicles (EVs) and hybrid electrical vehicles (HEVs).