Bharat's Research Group

Design of experiments to determine transport parameter of a porous media and kinetic parameters of energy storage and conversion materials

Enabling 3D structuring of battery electrodes:

For traditional battery designs based on homogeneous nonstructured porous electrodes, the through-plane tortuosity is the most relevant parameter describing ion conduction in the electrolyte phase, as it is dominated by through-plane conduction. However, modeling and optimization of the more recently proposed three-dimensionally (3D) structured electrode designs requires the values of both…

A significant part of our research focuses on Electrochemical Impedance Spectroscopy (EIS). For lithium-ion battery electrodes, the use of EIS based on a transmission line model (TLM) analysis to extract the effective transport and kinetic parameters is an active research area.

Semicircle does not  (always) represent Rct

Using direct analogy from flat electrode, often battery impedance spectra gets evaluated assuming flat electrode (which of course they are not) and the semi circle diameter (suppressed semi-circle in most cases) is thought be only Rct (charge transfer…

Computational tools can help design the batteries and enable efficient battery operations, one such example is the following work where detailed battery models have been used to come up with porosity and tortuosity (values and distribution) to minimize capacity fade. 

B. Suthar, P. W. C. Northrop, D. Rife, V. R. Subramanian, Effect of Porosity, Thickness and Tortuosity on Capacity Fade of Anode. J. Electrochem. Soc. 162, A1708-A1717 (2015).

Fast charging of Li-ion battery considering various fade mechanisms such as: 

1. Plating reaction
2. SEI reaction
3. Thermal degradation

Following publication covers our effort in fast charging algorithms using detailed electrochemical models. 

1. B. Suthar, V. Ramadesigan, S. De, R. D. Braatz, V. R. Subramanian, Optimal charging profiles for mechanically constrained lithium-ion batteries. Phys. Chem. Chem. Phys. 16, 277-287 (2014).

2. B. Suthar, P. W. C.…

Roll to roll battery electrode manufacturing process requires tuning of all the steps in order for the electrode to have better transport properties. Research in this sub-topic relates to quantifying the inhomogeneity that arises during the battery manufacturing steps and how can EIS based method help quantify such inhomogeneity. See more details in the following work:

R. Morasch, J. Landesfeind, B. Suthar, H. A. Gasteiger, Detection of Binder Gradients Using Impedance Spectroscopy and Their Influence on the Tortuosity of Li-Ion Battery Graphite Electrodes. J. Electrochem…