Research Projects

Next-generation alkali metal batteries (AMBs), including lithium (Li) and sodium (Na) systems, are poised to revolutionize energy storage with their high energy densities. However, significant challenges such as low Coulombic efficiency (CE), dendritic metal growth, and unstable anodes must be overcome to realize their potential. A comprehensive understanding of interfacial phenomena, SEI formation, and deposition kinetics is essential. Research has shown that electrolyte composition, solvent properties play crucial roles in enhancing CE and deposition uniformity by affecting metal morphology and SEI stability. Fluorinated solvents show promise in improving CE and uniform deposition, yet their mechanisms and optimal formulations remain underexplored. The project involves three core work packages (WP). WP1 aims to analyze kinetic and electrochemical factors impacting metal deposition, such as ion diffusion, SEI permeability, and electron transfer. Advanced techniques will be employed, including fast-scan voltammetry (10–1,000 V/s) using ultramicroelectrodes with radii under 25 µm to capture rapid electrochemical processes. Kinetic data will be interpreted using adapted Butler-Volmer or Marcus-Hush models. Various electrolytes, such as fluorophosphates and bis(fluorosulfonyl)imide, will be assessed for their impact on ion mobility and SEI properties, targeting a CE of ~99.9% in sodium metal cells and establishing benchmarks for optimal deposition. WP2 focuses on engineering current collectors (CCs) to promote uniform, dendrite-free metal deposition. This will involve CO2 laser direct-writing on nitrogen-doped polymers to create thin (less than 50 nm) carbon coatings with improved surface properties. Alloyed CCs produced via physical vapor deposition will be designed to enhance sodiophilicity and lithiophilicity, while 3D-structured CCs will help manage ion distribution and reduce mossy metal growth. The performance of these engineered CCs will be validated using Raman mapping and cryo-EM to confirm deposition uniformity, followed by testing in full anode-less cells paired with LiFePO4 or Na3V2(PO4)3 cathodes across C-rates from C/10 to 2C. WP3 encompasses the fabrication and performance assessment of anode-less pouch cells to evaluate their practical application and stability. Cells will be assembled in a controlled environment using optimized electrolytes from WP1 and engineered CCs from WP2. Galvanostatic cycling will be performed at various C-rates (C/10 to 2C) and at temperatures up to 60°C to simulate real-world conditions. Post-cycling analysis will include depth-profiling XPS for SEI composition, cryo-EM for inspecting the structural integrity of deposited metal, DNP NMR for in-depth SEI chemical characterization, and in-situ ECMS to track gas evolution and parasitic reactions. Overall, the outcomes of this research proposal will inform enhancements in AMB design for safe, reliable batteries suitable for EVs and large-scale energy storage.