Laboratory Electron Irradiation <i>Operando</i> Cell for Probing Synchrotron Beam Damage Mechanisms in Lithium-Ion Battery Electrolytes

Operando synchrotron techniques provide unique insights into the internal processes of lithium-ion batteries, but radiation-induced effects can alter cell behavior and compromise data interpretation. To better understand these phenomena, we developed an operando cell specifically designed for controlled irradiation studies, replicating synchrotron-like conditions, but at the laboratory scale. The electrolyte was selectively irradiated with an electron beam at doses of 5 and 10 kGy, and the resulting impacts on the electrochemical performance of a silicon-based electrode, gas evolution, and solid electrolyte interphase (SEI) composition were investigated. Irradiation led to immediate and dose-dependent degradation of cycling performance, with the 10 kGy-irradiated cells failing within four cycles. Gas analysis revealed increased formation of H2, CO2, CO, and CH4, the latter two gases being not produced in the nonirradiated cells, as well as the generation of specific compounds such as C2H6 and CH3CHO, absent in nonirradiated cells. While most gases showed dose-dependent production, H2 remained relatively insensitive to irradiation levels, likely due to residual water content. After irradiation followed by cycling of the cell, microscopic and electrochemical impedance spectroscopy analyses indicated significant modifications of the electrode surface and SEI morphology, with the formation of porous or inhomogeneous layers that promote further electrolyte degradation and gas release. These findings underscore the importance of accounting for beam-induced effects in operando studies, with a focus on the effect of the irradiation of the electrolyte, and provide a framework for understanding radiation-accelerated aging mechanisms in lithium-ion batteries.