A semiconductor physics based model for thermal characteristics in electronic electrolytic energy storage devices

A model for ultracapacitor capacitance and ion screening length based on semiconductor physics is presented in this paper. Screening length is related to capacitance as the plate-plate separation in a double-layer, and thus both are related to dissolved ion density in the electrolyte. Furthermore, this dissolved ion density can be expressed in terms of an effective bandgap assigned to the electrolyte/solvent pair. Therefore, by knowing the effective bandgap, we can explain the published experimental measurements of the dependence of capacitance and screening length on temperature. For electrolytes commonly used in ultracapacitor applications, the effective bandgap is estimated to be on the order of a few 100meV.

Automated summary

A model for ultracapacitor capacitance and ion screening length based on semiconductor physics is presented, showing the relationship between screening length and capacitance in a double-layer. Effective bandgap of the electrolyte/solvent pair is related to dissolved ion density, which in turn influences the capacitance and screening length dependence on temperature. The estimated effective bandgap for commonly used electrolytes in ultracapacitors is on the order of a few 100meV.