Stabilizing Interfaces of Lmr-NM//Gr Full Cells with Additives: A Deep Dive into SEI/Cei Characteristics, Electrolyte Consumption, and Sources of Mn Dissolution.

Cobalt-free Lithium- manganese-rich cathodes are excellent candidate cathode active materials (CAMs) to surpass performance and cost of LFP cathodes. However, the high-voltage activation and high Mn content of these CAMs lead to interfacial instability, which poses challenges for long-term cycling applications. In this work we discuss the results from a variety of tailored experiments designed to determine the electrochemical activity and effects on cycling metrics of electrolyte formulations containing TMSPi, VC, and/or LiDFOB. To understand the role of these additives in stabilizing interfaces, preformation experiments were conducted to determine individual additive effects on SEI/CEi. Mn-doped electrolytes were used to evaluate effectiveness of additive-generated SEIs in preventing the consequences of Mn deposition. Lastly, slow cycling tests at elevated temperature were used to determine electrolyte consumption rates at each electrode/electrolyte interface. Support from the Office of Vehicle Technologies of the U.S. Department of Energy (DOE), particularly from Carine Steinway, Tina Chen, Tien Duong, and Brian Cunningham is gratefully acknowledged. The submitted abstract 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.