# Tailored Porous Electrode Resistance for Controlling Electrolyte Depletion and Improving Charging Response in Electrochemical Systems

**Authors:** James W. Palko, Ali Hemmatifar, Juan G. Santiago  
**arXiv:** [1712.08826](https://arxiv.org/abs/1712.08826)  
**Date:** 2017-12-23  
**Summary page:** https://www.summarizepaper.com/en/paper/1712.08826v1/

## Key points

- Rapid charging and discharging of electrochemical cells can lead to localized depletion of electrolyte concentration
- Electrolyte depletion restricts charging rate and increases energy dissipation in systems with porous electrodes
- A theory is proposed to control and prevent electrolyte depletion by adjusting resistance in a porous electrode
- Increasing local spatial resistances of the solid electrode can improve charging rate with minimal change in energy loss
- An analytically derived expression for an electrode resistance profile is presented to ensure uniform electrolyte depletion
- Numerical simulations demonstrate that tailored electrode resistance profiles can enhance charging rate by up to approximately 2-fold
- Improvements are achieved without significantly affecting overall dissipated energy in the system
- The study provides insights into controlling electrolyte depletion and improving charging response in electrochemical systems with porous electrodes
- The proposed theory offers a promising approach for optimizing system performance while minimizing energy losses during rapid charge-discharge cycles.

## Summary

The rapid charging and discharging of electrochemical cells can result in localized depletion of electrolyte concentration, which has a significant impact on the system's time-dependent resistance. In systems with porous electrodes, this electrolyte depletion can restrict the rate of charging and increase energy dissipation. To address this issue, a theory is proposed to control and prevent electrolyte depletion by adjusting the value and spatial distribution of resistance in a porous electrode. Interestingly, the theory suggests that increasing local spatial resistances of the solid electrode itself can lead to an improved charging rate with minimal change in energy loss. An analytically derived expression for an electrode resistance profile is presented, which ensures highly uniform electrolyte depletion. This tailored resistance profile is then explored through numerical simulations to investigate its effect on the spatiotemporal dynamics of electrolyte concentration in a supercapacitor. The results demonstrate that implementing various tailored electrode resistance profiles can effectively avoid localized depletion and enhance the charging rate by up to approximately 2-fold. Importantly, these improvements are achieved without significantly affecting the overall dissipated energy in the system. Overall, this study provides valuable insights into controlling electrolyte depletion and improving the charging response in electrochemical systems with porous electrodes. The proposed theory offers a promising approach for optimizing system performance while minimizing energy losses during rapid charge-discharge cycles.