Figure 4 | Scientific Reports

Figure 4

From: Hybrid supercapacitor-battery materials for fast electrochemical charge storage

Figure 4

Charge storage mechanism in the hybrid electrode.

(a), Schematic representation of the fast charge - relaxation process. The green and black half-cylinders are indicative of the stored charge in PTMA and LiFePO4 respectively. The relative position of the red disk indicates the polarization of the constituents in the hybrid electrode. Except during the charge, the polarization is actually the equilibrium OCP for each component. Fast charging leads to a thermodynamically unstable configuration, characterized by evanescent co-existence of high potential PTMA+ with low potential LiFePO4 species forcing an internal charge transfer equilibration. The depicted situation is representative of 50% SOC, i.e., at equilibrium, only the LiFePO4 component will be charged. (b), Relaxation curves after charging the hybrid electrode at different rates and to different SOC. (c), Voltage profile at different discharge rates (the curves are shifted for clarity). For every discharge, the charge rate was 45 C.

Back to article page