Simulations of Electrochemical Phenomena in Energy Storage Systems

Join us on November 17 at 3:30 p.m. for this Sustainable Energy Seminar presentation by Weiyu Li, Assistant Professor of Mechanical Engineering.

Abstract

Plain language summary: Rechargeable lithium batteries power countless devices like phones and electric cars, but improving their performance requires understanding what happens inside the battery at a microscopic level. This talk explains how modeling the tiny structures in battery electrodes can predict how ions move and heat flows, which helps design better batteries. It also covers problems like lithium plating and dendrite growth—major causes of battery failure—and shows how adjusting charging methods and using special materials can prevent these issues. These insights lead to safer, longer-lasting, and more energy-dense batteries.

Full Abstract:

Rechargeable lithium batteries are electrochemical devices widely used in portable electronics and electric-powered vehicles. A breakthrough in battery performance requires advancements in battery cell configurations at the microscale level. This, in turn, places a premium on the ability to accurately predict complex multiphase thermo-electrochemical phenomena, e.g., migration of ions interacting with composite porous materials that constitute a battery cell microstructure.

Optimal design of porous cathodes requires efficient quantitative models of microscopic (pore-scale) electrochemical processes and their impact on battery performance. In this talk, I will discuss the derivation of effective properties (electrical conductivity, ionic diffusivity, and thermal conductivity) of a composite electrode comprising the active material coated with a mixture of the binder and conductor (the carbon binder domain or CBD). These effective descriptors ensure the conservation of mass, charge, and energy. When used to parameterize the industry-standard pseudo-two-dimensional (P2D) models, they significantly improve the predictions of lithiation curves in the presence of CBD. On the anode side, Li plating and dendritic growth are the leading causes of degradation and catastrophic failure of Li-ion and Li-metal batteries. Deep understanding of these phenomena would facilitate the design of strategies to reduce, or completely suppress, the onset of lithium plating on the graphite anode, and the instabilities characterizing electrodeposition on the metal anode. This would ensure the safety and performance of Li-metal batteries with liquid electrolyte, all-solid-state-Li batteries, aqueous Zn batteries, and Li-ion batteries under fast charging conditions. I will present my simulation results, which indicate that the adjustment of charging protocols can mitigate Li plating, and the use of anisotropic electrolytes and buffer layers can suppress dendrite growth.

This modeling framework has significantly advanced the understanding of electrochemical processes and transport phenomena in high-energy-density batteries, leading to improvements in safety, longevity, and energy density.