Rapid and Facile Manufacturing of All Dry Electrode Solid State Batteries for High Temperature and Voltage Applications

In Phase I, we successfully developed high-voltage solid-state Li-metal batteries using Soelect’s polymer/composite electrolytes and LiX® anodes, paired with a commercial spinel LiNi0.5Mn1.5O4 cathode. As we move into Phase II, our objective is to further advance high-voltage solid-state Li-metal batteries designed to withstand extreme conditions, including temperatures up to 100°C and voltages up to 4.6 V, specifically for Army applications.The project is the fabrication of solid-state cells using Soelect’s innovative electrostatic powder deposition (EPD) technology. It employs a revolutionary reverse assembly technique, which contrasts with traditional solid-state cell assembly methods that typically add the anode as the final step. In EPD, solid electrolyte and cathode powders are uniformly deposited onto Li foils without the need for liquid solvents. After deposition, a critical rolling step ensures connectivity between dry powder particles and their strong bonding to the Li foils, thereby enhancing the mechanical stability of the cell components. The resulting integrated Li anode || solid electrolyte || cathode cells are suitable for pouch cell assemblies. Unlike conventional slurry-based methods, our approach eliminates the need for slurry mixing, coating, drying, and solvent recovery. While other solid-state technologies require multiple stages such as powder mixing, kneading, milling, and laminating, EPD simplifies the process to just two brief mixing and spraying steps, making it more suitable for commercialization with readily available powder deposition and rolling equipment.To ensure the quality of the EPD process and the integrity of interfaces between the solid electrolyte and electrodes, we will rigorously test the integrated electrodes and final assembled cells by characterization techniques. These will include CV, charge/discharge cycling, rate capability, EIS, and GITT to assess the electrochemical performance. Additionally, post-mortem analyses using SEM, EDS, XRD, XPS, TGA, and DEMS will help uncover underlying failure mechanisms.The proposed cell designs will address several critical challenges, such as dendrite growth in Li anodes, limited electrochemical stability window, incompatible interfaces between solid electrolytes and electrodes, and high interfacial resistance in solid electrolytes. Furthermore, the design will tackle issues like microcracks, gas evolution, limited working potential, accelerated surface degradation, and transition metal dissolution in high-voltage cathodes. As a result, the cells will feature robust mechanical integrity, intimate interfaces with low interfacial resistance, and high thermal and electrochemical stability, contributing to long-term cycling stability. Finally, we will conduct a comprehensive evaluation of the scalability and cost considerations for Soelect’s solid-state Li-metal batteries, with the aim of preparing for mass production in subsequent phases of the project.