Since its discovery, the high-voltage spinel oxide LiNi_0.5Mn_1.5O₄ (LNMO, sg: Fd-3m) has been widely pursued as a promising cathode for next generation Li-ion batteries due to advantages that include the following: high operating voltage, excellent rate capability and low manufacturing cost (1, 2). However, the LNMO cathode when paired with graphite shows poor capacity retention and increased cell impedance due to oxidation of the organic liquid electrolyte and Mn²⁺ migration onto the anode (2, 3). Herein, we aim to understand the causes of poor capacity retention in LNMO/graphite full cells and systematically address those issues with various electrode modification strategies. Cycling performance of cells with carbon-nanotube (CNTs) in the LNMO electrode (LNMO-CNT), and with a thin layer of Al₂O₃ on the graphite electrode (Gr-Al₂O₃), is examined in half, full and three-electrode cell configurations. The cells with LNMO-CNT electrode show significantly lower cell impedance than cells with LNMO electrodes (without the CNT). Additionally, cells with the Al₂O₃-coated graphite electrode show improved capacity retention compared to cells with the uncoated graphite. Furthermore, cells containing Li₄Ti₅O₁₂ anodes display the best capacity retention. We investigate and compare the physiochemical changes in electrodes and electrolyte using various diagnostic techniques; data from these experiments will be reported during the presentation.

References:

1. M. M. Thackeray, W. I. F. David, P. G. Bruce and J. B. Goodenough, Materials Research Bulletin, 18, 461 (1983).
2. S. Patoux, L. Daniel, C. Bourbon, H. Lignier, C. Pagano, F. Le Cras, S. Jouanneau and S. Martinet, J Power Sources, 189, 344 (2009).
3. F. Zou, H. C. Nallan, A. Dolocan, Q. Xie, J. Y. Li, B. M. Coffey, J. G. Ekerdt and A. Manthiram, Energy Storage Materials, 43, 499 (2021).

Acknowledgements: This document has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357.