A review of advanced separators for rechargeable batteries

Abstract

The separator is a key component for rechargeable batteries. It separates the positive and negative electrodes to prevent short-circuit of the battery and also acts as an electrolyte reservoir facilitating metal ion transportation during charging and discharging cycles. Separator selection and usage significantly impact the electrochemical performance and safety of rechargeable batteries. This paper reviews the basic requirements of rechargeable battery membrane separators and describes the features, benefits and drawbacks of different types of membrane separators. The structure, characteristics, fabrication, modification, and performance of the separators are discussed, including the microporous membrane, modified microporous membrane, nonwoven membrane, cellulose-based membrane, and electrolyte membrane. Finally, it also provides the outlook and suggests future directions for this field of study. • Separator is critical to the performance and safety of the rechargeable batteries. • The design principles and basic requirements for separators are overviewed. • The modification strategies in tailoring the separators' properties are discussed. • Separators with high-temperature resistivity and better safety are desirable.