Interface Issues in Solid and Gel Polymer Electrolytes for Sodium Batteries

Abstract

Lithium-ion batteries, commonly used in many portable devices, are popular due to their high energy output and versatile applications. However, there is a need to develop an alternative due to the high cost of lithium and ethical concerns about lithium mining. Sodium-ion batteries are a promising substitute due to sodium’s similar chemical properties to lithium, abundance, low cost, and environmentally friendly extraction process. However, scientific advancements in sodium-ion battery technologies have been impeded for a number of reasons: mainly the interface instability between the electrolyte and sodium anode. Interface instability can occur when chemical reactions at the interface cause the battery to short circuit and when sodium dendrites form in the voids at the interface with the sodium metal and electrolyte. In an attempt to address these dendrite issues, researchers have turned to solid state electrolytes. Additionally, liquid electrolytes, commonly used in lithium-ion batteries, cannot be used in sodium batteries due to safety issues; thus gel and solid state electrolytes (SSEs) are especially important in the context of sodium batteries. This paper intends to determine what specific problems, with an emphasis on interface stability, are seen in solid polymer electrolytes (SPEs) and gel polymer electrolytes (GPEs) while addressing strategies to broaden the applicability of sodium-ion batteries.