Enabling Fast Charging with Organosilicon-Containing Electrolytes

Abstract

Electric vehicle (EV) adoption is growing worldwide, with EVs offering the benefits of zero emissions, increased reliability, and reduced maintenance costs.1 However, there remain battery-related challenges for EVs, including slow charging times.1 There is therefore a significant need for lithium-ion batteries (LIBs) that can cycle at fast rates. Unfortunately, accelerated cycling rates can result in faster capacity fade, due to the kinetic limitations of current battery materials, leading to detrimental repercussions such as lithium plating. Lithium plating can reduce the active lithium inventory, increase electrolyte reactivity, and cause internal shorts.2 One approach to enable stable fast charge cycling is the development of novel battery electrolytes designed to facilitate intercalation kinetics and mitigate lithium plating. Silatronix, Inc. is a developer of functional organosilicon additives and solvents that have previously been shown to increase electrolyte thermal stability,3 and reduce gassing in LIBs.4 In this study, we investigated the impact of organosilicon additives on fast charge cycling in nickel-rich batteries (NMC622 and NMC811 cathodes). We find that these organosilicon additives improve cycling capacity, impedance, and gassing during fast charging. We employ post-analysis techniques including gas extraction for gas chromatography, electrolyte extraction for NMR, and electrode extraction for XPS to understand how organosilicons provide the observed superior fast charge cycling performance. Sanguesa, J. A., et al. Smart Cities 2021, 4, 372.Liu, Y., et al. Nature Energy 2019, Guillot, S.L., et al. Journal of the Electrochemical Society 2017, 164, A1907.Guillot, S.L., et al. Journal of the Electrochemical Society, 2021, 168, 030533.