Li-ion Batteries with 3-D Structured Anodes to Minimize Inactive Materials and Improve Safety

In order to accelerate widespread electric vehicle adoption, improving battery energy densities, charge rates, manufacturing costs, and safety is imperative. Herein, we propose a scalable manufacturing process to improve LIB cell design using 3-D electrode architectures which will minimize inactive material (30% decrease) leading to a 15% increase in cell energy density (330 Wh/kg) and a 10% decrease in cell cost ($82/kWh) while simultaneously improving safety by eliminating Li-plating. The 3-D architectures enable the use of high areal loading graphite (Gr) and graphite/silicon blend (Gr/Si) electrodes (5-8 mAh/cm2) by enabling improved mass transport of Li-ions into the depth of the electrode. This allows for safe and fast charging of thick electrodes at relevant C-rates (2C) without Li plating. The goal for this Phase I SBIR/STTR project is three-fold: (1) Demonstrate a laser ablation process to generate 3-D structures in 7-8 mAh/cm2 Gr and Gr/Si electrodes using commercial IR lasers compatible with high throughput, low-cost manufacturing; (2) Perform a design-of-experiments using single-layer pouch cells with various 3-D geometries to optimize energy density and charge rate, ensuring compatibility with high throughput manufacturing; and (3) Manufacture and test multilayer pouch cells (>2 Ah) using the optimized geometry to demonstrate a 30% reduction in inactive materials and increased safety by showing the elimination of Li-plating. The proposed laser manufacturing processes is drop-in compatible with today’s LIB manufacturing and can be directly integrated into high-speed roll-to-roll electrode manufacturing lines, such as those being built in LIB “gigafactories” currently being built across the United States. As a result, the CapEx investments are significantly reduced, enabling us to scale rapidly at a low cost, while simultaneously leveraging the already extensive investments in and optimization of LIB manufacturing. This contrasts with next-generation battery chemistries such as Li-metal anodes or solid-state batteries which require a redesign of the manufacturing process and will massive investments in time and resources to scale to be cost competitive with LIBs.