Interfacing Si-Based Electrodes: Impact of Liquid Electrolyte and Its Components

Abstract

As the demand for mobile energy storage devices has steadily increased during the past decades due to the rising popularity of portable electronics as well as the continued implementation of electromobility, energy density has become a crucial metric in the development of modern batteries. It was realized early on that the successful utilization of silicon as negative electrode material in lithium-ion batteries would be a quantum leap in improving achievable energy densities due to the roughly ten-fold increase in specific capacity compared to the state-of-the-art graphite material. However, being an alloying type material rather than an intercalation/insertion type, silicon poses numerous obstacles that need to be overcome for its successful implementation as a negative electrode material with the most prominent one being its extreme volume changes on (de-)lithiation. While, as of today, a plethora of different types of Si-based electrodes have been reported, a universally common feature is the interface between Si-based electrode and electrolyte. This review focuses on the knowledge gained thus far on the impact of different liquid electrolyte components/formulations on the interfaces and interphases encountered at Si-based electrodes.