Cell components – Electrolytes | Non-aqueous and solvent-based electrolytes

An electrolyte that serves as an ionic conductor, is an indispensable component for electrochemical cell devices. The electrolyte is generally sandwiched between the positive electrode and negative electrode. In fact, both the electrolyte properties and electrode-electrolyte interfaces together can affect the battery performance. For most commercial electrolytes used today are formed by dissolving electrolyte salt in non-aqueous systems (organic solvents), where cations and anions are separated by non-aqueous solvents via solvation sheaths. Actually, electrolyte concentration not only affects the battery cost and manufacturing but also impacts the battery performance through liquid diffusion and interfacial properties. In this chapter, we firstly offer an overview of the design principle of creating non-aqueous electrolytes to meet requirements for practical application, followed by focusing on analyzes research progress in the non-aqueous and solvent-based electrolytes used in lithium-ion batteries, including conventional concentration electrolytes, high-concentration electrolytes, localized high-concentration electrolytes and low-concentration electrolyte. The influence of properties of different concentration electrolytes for batteries is discussed in detail. Finally, we provide perspectives on the current limitations and future directions of non-aqueous electrolytes. We hope that this chapter will provide comprehensive guidance in designing and developing non-aqueous electrolytes for high-performance batteries.