Tailoring the Properties of Gel Polymer Electrolytes for Sodium-Ion Batteries Using Ionic Liquids: A Review.

Ionic liquids are an extraordinary group of compounds, fully ionic in structure like inorganic salts but with low melting points, that resemble organic molecular solvents. Their chemical, electrochemical, and thermal stability is what draws the attention and enables their use in many applications, including electrochemical power sources. Even though they are no longer considered eco-friendly because of nonnegligible toxicity and long bioaccumulation, they can still be efficiently recovered, purified, and reused. These attributes can be harvested to enhance the properties of gel polymer electrolytes for the emerging sodium-ion batteries. The variety of anions and cations for ILs and their influence on the final properties of the compound opens the road to tuning the properties of gel polymer electrolytes. Ionic liquids as plasticizers constitute a major part of gel polymer electrolytes (average of 70 wt%) and hence, they affect the fundamental properties of gel electrolytes like ionic conductivity and electrochemical window. They also improve the safety features of sodium-ion batteries, which is relevant for their anticipated applications in stationary energy storage and electric vehicles. The presented review paper aims to explain the relationship between the cation and anion in ionic liquid and the properties of gel electrolytes for sodium-ion batteries.

Gel Polymer Electrolytes with Talc as a Natural Mineral Filler and a Biodegradable Polymer Matrix in Sodium-Ion Batteries.

A gel polymer electrolyte based on poly(vinyl alcohol) (PVA) is used in sodium-ion batteries (SIBs). The use of biodegradable and water-soluble polymer potentially reduces the negative environmental impact. The other components include sodium salt (NaPF6 ), sulfolane (TMS) as a plasticizer and talc. For the first time, natural and abundant talc has been used as an inert filler in a gel polymer electrolyte. The best results were obtained for moderate amounts of filler (1 and 3 wt%). Then, an increase in the conductivity, transference numbers, and thermal stability of the membranes was observed. Moreover, the presence of talc had a positive effect on the cyclability of the hard carbon electrode. The discharge capacity after 50 cycles of HC|1 % T_TMS|Na and HC|3 % T_TMS|Na was 243 and 225 mAh g-1 , respectively. The use of talc in gel polymer electrolytes containing sodium ions improves the safety and efficiency of SIBs.

From waste to energy storage: calcinating and carbonizing chicken eggshells into electrode materials for supercapacitors and lithium-ion batteries.

The presented study aims to explore the potential sources of common bio-wastes that could be successfully processed without any leftovers into materials for energy conversion and storage devices. We used chicken eggshells as an environmentally friendly precursor for electrode fillers in electrochemical capacitors (calcinated OS600 and OS900) and anode materials in Li-ion batteries (carbonized EM600 and EM900). Both groups of materials were obtained at two different temperatures to investigate the influence of their composition and properties on the electrochemical performance. Electrochemical capacitors with OS600 and OS900 substituted for 10 wt% of commercial activated carbon supplied similar capacitances, with OS600 stabilizing the long-term performance of the device. Also, both obtained anode materials are suitable for operation in Li-ion batteries, supplying a capacity of around 280 mA h g-1. Notably, EM900 is characterized by a well-developed structure, and as an anode, it exhibited better capacity retention of over 84%.