Three‐Component Solid Polymer Electrolytes Based on Li‐Ion Exchanged Microporous Silicates and an Ionic Liquid for Solid‐State Batteries

Abstract

Solid polymer electrolytes (SPEs) represent one of the most suitable options to overcome durability and safety issues. Herein, three‐component SPEs based on poly(vinylidene fluoride‐co‐hexafluoropropylene) as a binder, the 1‐butyl‐3‐methylimidazolium thiocyanate ionic liquid as an ionic conductive component, and zeolites, to improve SPE ionic conductivity and electrochemical stability, are prepared and characterized. Different zeolite and zeolite‐like structures (clinoptilolite, ETS‐4, and ETS‐10) are used, and the effect of lithium‐ion exchange in their structures is evaluated. A clear influence of the ion exchange process on the crystallinity of the prepared samples is observed, which plays a key role in the conduction mechanisms. The ionic conductivity of the samples at room temperature is of the order of 10−3 S cm−1, making them suitable for battery applications. The assembled batteries show promising results at room temperature, proving that the ion exchange has a positive effect on battery performance. The ion‐exchanged clinoptilolite sample presents the best performance at a prolonged cycle number, with an initial discharge capacity of about 130 mAh g−1 at C/10, and a capacity retention of 70% after 50 cycles. Thus, it is proved that the ion exchange process in microporous silicates represents a suitable strategy to develop high‐performance solid‐state lithium‐ion batteries (LIBs).