Figure 1. Hybridization principle and materials.

(a), Voltage vs. capacity profiles for typical capacitor and battery materials as well as for traditional hybridization. The stored charge (Q) is low given the low specific capacity of the capacitive component and the LIB plateau vanishes at high charge-discharge rates. (b), Voltage profile of the hybrid PTMA-LiFePO₄ electrode at a current density of 26 mAh/g_hybrid. Both plateaus are discernible in charge and discharge and correspond to distinct redox processes of PTMA and LiFePO₄. For constituents mass ratio of 1.6, the capacity contribution ratio of each component is ~1, corresponding to a specific capacity of ~126 mAh/g_hybrid.