The M&MS Group contributes to several key DOE programs over areas ranging from electrode modeling, understanding cation and electron transport, active materials development.

Sodium-ion batteries: While lithium-ion systems have become established in several markets, alternative systems based on sodium-ions are under consideration due to advantages including lower materials costs and low state-of-charge safety.   Within the M&MS Group our focus is on the development and understanding of next generation materials systems based on new sodium-ion anode and cathode materials. 

• Sodium-Ion Anodes: We have been  determining new charge storage mechanisms for Na-ion specific anode systems (e.g. NaPb, Na₃P) working to identify the role of reversible structural transformations, electrochemical reversibility, stability, and safety in these emerging systems.
• Sodium-ion Cathodes: Structurally sodium-based cathodes are similar to lithium-ion cathodes but with possible significant differences in sodium-ordering, layering schemes, polymorphs, and cation coordination. In these systems, novel electroactive materials have been isolated and the differences in performance can be traced to the differences between sodium-sites, alternative diffusion pathways, and  overall materials properties (e.g. conductivity).  Recent work: 
  • “Unraveling the Formation Mechanism of NaCoPO₄ Polymorphs”  J. Solid State Chemistry, (2020) DOI:10.1016/j.jssc.2020.121766
  • “Disrupting the Na⁺/Vacancy Ordering in P2-type Na(NiMn)O₂ Cathodes in Na-Ion Batteries” J. Physical Chemistry C, (2018) DOI:10.1021/acs.jpcc.8b05537

Silicon-Based Anodes: While graphitic carbon is an established anode system for lithium-ion energy storage systems, the next generation of LIB anode materials are projected to contain silicon materials as an active component as a pathway to increase energy density.  Within our group we have focused on electrode stability, prelithiation studies, and issues associated with full cell cycling.  Recent work:

• Electrodes: Electrode level studies are an important area of research for silicon because of the complex interactions between silicon, binder, electrolyte, and conductive additive.  Notably issues associated with blended electrodes (silicon/graphite) are seen due to the different surface chemistry of the electroactive materials.
  • “Capacity Fade in High Energy Silicon/Graphite Electrodes of Lithium-Ion Batteries” Chem. Comm. (2018) DOI:10.1039/c8cc00456k
  • “Investigations of Silicon Thin Films as Anodes for Lithium-Ion Batteries” ACS Applied Materials and Interfaces (2018) DOI:10.1021/acsami.7b13980
  • “The Electrochemical Stabilization of Silicon Anodes via a Locally Concentrated LiNO₃ Complex” J. Electrochem Society (2023) 10.1149/1945-7111/acad35
  • “Calendar Aging of Silicon-Containing Batteries” Nature Energy (2021) DOI: 10.1038/s41560-021-00883-w
• Prelithiation: An issue associated with silicon-based electrodes has been the large irreversible capacity seen in early cycles due to various break-in processes, slow initial diffusion of lithium into crystalline silicon, and surface reactivity.  One way around this problem has been to use a sacrificial lithium source to counter this phenomenon to counter the loss of active lithium to the system.
  • “Beneficial Effect of Li₅FeO₄ Lithium Source for Lithium-ion Batteries with a Layered NMC Cathode and a Silicon Anode”  Journal of the Electrochemical Society (2020) DOI:10.1149/1945-7111/abd1ef
  • “Liquid Ammonia Chemical Lithiation: An Approach for Higher Energy and High Voltage Silicon/Graphite Li_1+x[Ni_0.5Mn_1.5]O₄ Lithium-ion Batteries”  ACS Applied Energy Materials (2020) DOI:10.1021/acsaem.9b00695
  • “Cathode Pre-Lithiation/Sodiation for Next-Generation Batteries” Current Opinion in Electrochemistry (2022)  DOI:10.1016/j.coelec.2021.100827

Photo-Assisted Electrochemistry The interaction of white light and lithium-ion battery cathodes has been found to enhance the rate capability of materials in an electrochemical cell. This project uses detailed characterization methods, cell design, and modeling efforts to better understand the observation that the rate capability of an electrochemical cell can be enhanced by interactions with white light.

• Cathode Fast Charging
  • “Photo-accelerated fast charging of lithium-ion batteries” Nature Communications (2019) DOI: 10.1038/s41467-019-12863-6

  • “Correlating wavelength dependence in LiMn₂O₄ cathode photo-accelerated fast charging with deformations in local structure” Cell Reports Physical Science (2022) 10.1016/j.xcrp.2022.101051