Designing polymer electrolytes for sodium-based batteries

Here, we offer an overview of our recent developments on innovative polymer electrolytes for sodium-ion batteries. Polymer electrolytes were prepared through different techniques, including simple solvent casting and UV-induced photopolymerization (UV-curing), being simple, low-cost and easily scalable to an industrial level. All samples were thoroughly characterized in the physico-chemical and electrochemical viewpoint. They exhibited an excellent ionic conductivity of 1 mS cm-1 at 25 °C and wide as and wide electrochemical stability window (4.7 V vs. Na+/Na), which ensure safe operation at ambient conditions. Electrochemical performances in lab-scale devices were evaluated by means of cyclic voltammetry and galvanostatic charge/discharge cycling using different electrode materials (prepared by water-based procedures exploiting green carboxymethylcellulose as binder). Work on Na-ion polymer batteries for moderate temperature application is at an early stage, only lab-scale cells were demonstrated so far. Nevertheless, with the appropriate choice and optimization of electrode/electrolyte materials (and successful combination thereof), the intriguing characteristics of the newly developed polymer electrolytes here presented postulates the possibility of their effective implementation in safe, durable and high energy density secondary Na-based solid-state devices conceived for green-grid storage and operating at ambient and/or sub-ambient temperatures