Engineering ion solvation and charging rate near the electrolyte-electrode interface
The deposition rate of lithium ionss and cycling stability during fast charging are tightly linked to the solvation structure of lithium ions in bulk electrolytes and near electrolyte-electrode interface. This project will combine theory and simulation to investigate the spatial variation of the dielectric screening, the ion solvation structure near the interface, and the solvent reorganization free energy. The goal is to identify the molecular properties, such as charge distribution and polarizability, that impact the heterogeneous features near electrode.
Prevention of Mechanical Failure in Battery Electrodes During Fast Charging
The development of fast charging Li-ion batteries (<10 minutes at a charging station) will greatly accelerate the adoption of electric vehicles by consumers. One major technical hurdle is the mechanical degradation of battery electrodes during cycling, which leads to reduced charging capacity and battery life. This project will use nano-mechanical measurements to directly measuring strength, deformation and failure of individual particles at high strain rates and under cyclic loading. Mechanical failure mechanisms will be correlated to cycle life, power output, capacity fade and microstructural changes during battery testing.
Materials search for fast charging of solid state batteries
We seek to identify new combinations of solid electrolyte, anode and cathode that mitigate common barriers to fast charging, including interfacial kinetics and mechanical effects. We will identify the most promising candidates by combing data science methods with chemical, structural, and electronic descriptors of materials that contribute to these properties. We seek to identify combinations with minimal or no interfacial chemistry, and suitable coatings that can mitigate interfacial chemistry and expand the electrochemical stability window of commonly studied solid electrolytes.
Fair Market Valuation of EV Batteries in the Circular Economy
With the share of EVs for transportation growing rapidly in many countries, it becomes imperative to examine economically viable use cases for batteries that are no longer suitable for primary mobile applications. This work seeks to conduct a micro-economic analysis of used batteries emerging from transportation-related applications that could be deployed in a second life, before moving to a recycling or disposal stage. The research will develop an economic valuation framework that determines the fair market value of batteries entering their 2nd-life based on their assessed state of health at the end of their first life. This fair market valuation will also consider the expected salvage value that end-of-life EV batteries are likely to yield once the nascent recycling industry for batteries reaches full scale.
Designing and Evaluating Battery Recycling Unit Processes
The overall goal of the proposed research is to integrate the design of recycling processes with battery operation and supply chain logistics. Informing process design with practical battery performance requirements and more efficient logistics will accelerate the transition to a circular battery economy. Within this battery economy, we investigate element-specific recovery focused first on lithium, cobalt, and nickel. We pursue three complementary objectives in this proposal: (1) determine the effect of feedstock composition (e.g., homogeneous vs. mixed stream) on separation process performance; (2) evaluate the effect of centralization on the separation performance of novel battery recycling unit processes; and (3) establish relationships between separation process performance and battery performance. We focus on three classes of separation techniques: metallurgical, membrane, and adsorption processes. These efforts advance two C2E2 Research Pillars: new processing technology for recycling and environmental impact assessment tools.
A Decision-Support Model for Retired Li-Ion Automotive Batteries
Today, electric vehicles (EVs) are the leading option for making transportation more sustainable, but with the ever-increasing growth of EVs, there is emerging concern about what to do with the retired batteries. The first wave of these retired batteries is expected by early EV adopters by 2025, with over 45,000 battery packs (containing tens of millions of Li-Ion cells) coming out of service. When batteries are retired from automotive service they still have from 50% to 70% of their initial capacity, which opens the possibility to repurpose them for other less demanding applications until they are eventually recycled. Possible applications include behind the meter energy storage for peak shaving, demand response, and power quality. Alternatively, grid-connected batteries also can provide frequency regulation, renewables smoothing, ramping support, and peak shaving, to name a few. Each of these 2nd life applications will place different demands on the battery, affecting its remaining useful life. There are four significant challenges to overcome to make repurposing or reusing retired batteries a viable option. Methods are needed to 1) quickly, affordably, and reliably assess the state-of-health of the battery pack/cells, 2) evaluate the remaining useful life of the pack/cells for different 2nd life applications, 3) determine the economic value of the pack/cells for sellers and buyers of repurposed batteries and 4) make repurposing batteries inexpensive enough to compete with the ever-declining costs of new Li-Ion batteries. The goal of this project is to develop an integrated physics-based and technoeconomic model to assess whether a battery system coming out of automotive service should be recycled directly or has sufficient economic value to be repurposed for a particular 2nd life application, and if so, what is the value?