Rational design of battery cathode materials and battery cell prototyping at BEACONS

Abstract:  

Current Li ion batteries (LIBs) are improved versions of the 1991 Sony LIB based on graphite anode, organic liquid electrolytes, and LiCoO2 layered oxide cathode. In the commercial applications of LIBs, cathode materials are known to be the critical component in determining the battery cost (~50% of material cost) and the energy storage capacity (cell capacity = ~1/3 cathode capacity). Over the last 30 years, the initial LiCoO2 cathode (~140 mAh/g charge capacity) has evolved to high capacity cathodes with increasing Ni content replacing Co starting from Li(Ni1/3Co1/3Mn1/3)O2 or NCM111 (~160 mAh/g) to NCM433, NCM532, NCM622, NCM721, NCM811 (~200 mAh/g), and LiNiO2 (> 200 mAh/g). With 70-80% Ni in NCM cathodes (theoretical capacity of ~275 mAh/g), more than 70% of Li can be utilized in the electrochemical reactions in realizing the high-capacity cathode. However, in the fully charged state of LIBs, cathode materials are very unstable toward chemical reactions (irreversible reactions with electrolytes, oxygen evolution and phase changes) and mechanical degradation (interface crack formation). Specifically, the high-Ni NCM cathode materials are known to have large volume change (-7%) at 80% delithiation with the majority of volume change (DV/V = -5%) happening at Li delithiation from 70% to 80% leading to the mechanical cracking of the secondary cathode particles. In this talk, we will discuss multiscale modeling study based on density functional theory (DFT) calculations to examine the atomic and electronic structure origins of the cathode degradation mechanisms.[1,2] Based on the identified microscopic mechanisms at atomic scales, surface and mechanical stabilization methods are designed for experimental validations. The findings in material design research are the basis of current high-throughput robotic synthesis work for the validation experiments. After successfully synthesizing the designed cathode materials, prototype battery cells (18650 and pouch cells) will be produced at the battery R&D line at UTD. University of Texas at Dallas has established the BEACONS center (https://beaconsusa.org/) to strengthen the US energy storage systems industry through an improved domestic supply chain, new battery innovations and a qualified workforce. We will discuss the center facility for R&D line battery production of pouch cells and cylindrical cells (18650, 21700). We will highlight the advanced manufacturing scale-up of battery materials based on AI/ML methods and advanced metrology for accelerated battery manufacturing.

Bio:

Professor Victor R. Vasquez has served in the Department of Chemical and Materials Engineering (CME) at the University of Nevada, Reno (UNR) since 1999, where he is currently professor and department chair. His research spans computational modeling, applied thermodynamics, process systems engineering, and the development of novel materials for chemical engineering and materials science applications. He earned a Licentiate (five-year degree) in chemical engineering from the University of Costa Rica (1990) and MS and PhD degrees in chemical engineering from the University of Nevada, Reno (1997, 1999). A dedicated educator at both the undergraduate and graduate levels, he has also provided extensive service to the chemical engineering and materials science professions. He currently serves on the Condensed Matter and Materials Research Committee (CMMRC) of the National Academies