We have made considerable advances in using colloidal particles as templates for electrodeposited three-dimensionally structured battery electrodes, and in understanding energy transport within dense suspensions of redox active colloidal particles. We have found that by using colloidal templating, we can design 3D structured battery electrodes with the appropriate free volume to accommodate the large volume changes present during cycling of high energy density alloying-based (e.g., Si and Sn) Li-ion anodes, as well as provide the required pathway for efficient lithium ion and electron transport to provide good rate performances. In a related area, we have been investigating energy transport in redox-active colloids (here the colloids serve as the energy storage material, rather than as a sacrificial template). Somewhat unexpectedly, we discovered that the fluorescence of ethyl-viologen derivatized redox active colloids was a strong function of the colloid’s electrochemical state. Using this, we are able to follow the inter-colloidal energy transport in a dense array of redox-active colloids over distances exceeding 20 microns as the colloids undergo reversible oxidation and reduction. These colloids have been proposed as the basis of flow battery energy storage systems, and understanding energy transport in dense suspensions of redox active colloids is an important requirement to advance the application of these materials.

Colloids for energy storage: Visualizing energy transport in redox-active colloids and using colloids as templates for 3D-structured li-ion battery electrodes

ACS Spring Meeting 2021

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