Laser Ablation of High-Loading Electrodes to Improve Performance of Li-Ion Batteries in Behind-the-Meter Storage (BTMS) Applications
Authors: Pereira Drew J. , Tancin Ryan J , Ha Yeyoung , Trask Stephen E. , Finegan Donal P. , Tremolet de Villers Bertrand J. , Harrison Katharine L. 
Published: December 2024

Behind-the-Meter Storage (BTMS) is a battery-based, stationary energy storage system that is connected to the residential or industrial customer’s side of the electrical grid utility service meter. BTMS systems enable consumers to (A) economically schedule charging and usage of stored energy, (B) store and use energy from on-site generation, especially from inconstant, renewable sources like solar and wind, and (C) avoid overworking the grid during peak hours via supplementation with stored energy. BTMS battery performance requirements and general priorities differentiate from other applications, like EVs, which has prompted the development of batteries with tailored electrode and electrolyte materials. These materials prioritize low cost, avoiding critical materials; high safety, mitigating thermal runaway; and longevity, achieving 8000 cycle and 20-year shelf lives.
Lithium titanate (Li4Ti5O12, LTO) is a promising anode candidate for BTMS applications due to its high safety and stability, while maintaining an acceptable 160 mAhg-1 reversable capacity and composition of reasonably abundant materials.[1] Specifically, LTO has a high working voltage, which helps to prevent Li dendrite formation, improving safety. Furthermore, LTO, a “zero strain” material, has negligible lithiation-based volume change, leading to less active material loss upon cycling. Lithium manganese oxide (LiMn2O4, LMO) has been paired with LTO for BTMS applications in the past due to its safety, low cost (abundancy and critical material-free), and decently high operating voltage.[2-4] However, the low specific capacity of LMO limits energy density. While not the highest priority for BTMS applications, increasing energy density will enable BTMS deployment in space constrained applications as well as decrease total cost of the system. Therefore, improving volumetric energy density via the use of high-loading electrodes is of interest. A concern with the use of high-thickness, high-tortuosity, and low-porosity electrodes is that limitations arise with regard to electrode wettability, rate capability, and general performance, especially when paired with the high-stability, but also high-viscosity, ethylene carbonate-based electrolytes.[4] Previous studies have shown that limitations in electrode wettability and rate capability may be addressed by employing a scalable laser structuring technique on the electrodes prior to cell assembly.[5]

Therefore, the study presented here focuses on the understanding of how structuring of high-loading LTO/LMO electrodes via laser ablation will impact cell performance. Specifically, a comparison is provided for cells with standard electrodes, a standard anode and ablated cathode, an ablated anode and standard cathode, and both electrodes ablated. Details of a novel laser structuring method will be provided in addition to material characterization as well as electrochemical characterization focused on rate capability and cycle life as they apply to BTMS requirements.
This work was authored in part by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding was provided by the U.S. Department of Energy's Vehicle Technologies Office under the Behind-the-Meter Storage (BTMS) Consortium directed by Fernando Salcedo and managed by Anthony Burrell. The electrodes used in this manuscript are from Argonne's Cell Analysis, Modeling and Prototyping (CAMP) Facility, which is fully supported by the DOE Vehicle Technologies Office (VTO). The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes.
References
1. Xu, Gaojie, et al. "Li4Ti5O12-based energy conversion and storage systems: Status and prospects." Coordination Chemistry Reviews 343 (2017): 139-184.
2. Ha, Yeyoung, et al. "Designing Li4Ti5O12/LiMn2O4 Cells: Negative-to-Positive Ratio and Electrolyte." Journal of the Electrochemical Society 170.5 (2023): 050520.
3. Ha, Yeyoung, et al. "Impact of Electrode Thickness and Temperature on the Rate Capability of Li4Ti5O12/LiMn2O4 Cells." Journal of the Electrochemical Society 168.11 (2021): 110536.
4. Ha, Yeyoung, et al. "Long-term cyclability of Li4Ti5O12/LiMn2O4 cells using carbonate-based electrolytes for behind-the-meter storage applications." Energy Storage Materials 38 (2021): 581-589.
5. Dunlap, Nathan, et al. "Laser ablation for structuring Li-ion electrodes for fast charging and its impact on material properties, rate capability, Li plating, and wetting." Journal of Power Sources 537 (2022): 231464.