Proton conducting electrolytes composed of chondroitin sulfate polysaccharide and citric acid

Abstract

Novel electrolytes composed of chondroitin sulfate A (CSA) and citric acid (CA) have been prepared using a clean, safe, and fast route. These electrolytes exhibit different physical-chemical properties, depending on the amount of CA. For X > 82.3%, where X is the mass ratio, in %, of CA/(CA + CSA), whitish polycrystalline powders result. Lower amounts of CA leads to the production of translucent, amorphous films, sticky for X = 75.6 and 82.0, brittle for X < 43.6 and crack-free, self-standing for 43.6 < X < 75.6%. The results obtained provide evidence that, at low pH, strong hydrogen bonding interactions take place between the anionic sulfonic and carboxylic groups of CSA and CA. CA exerts a key role, acting as a cross-linker and proton source, while simultaneously influencing sample morphology. At room temperature the highest ionic conductivity is achieved at X = 60.8%. A significant enhancement of the ionic conductivity of this sample occurs with the increase of relative humidity (RH) (from 3.1 × 10 −7 to 3.7 × 10 −2 S cm −1 30% for RH = 30 and~100%, respectively).

Looking beyond biology: glycosaminoglycans as attractive platforms for energy devices and flexible electronics

“…Overall, thermal stability studies consistently indicate that the degradation temperature for GAGs ranges between 200 and 300 1C, under both an inert and an oxidative atmosphere. 47,[104][105][106][107] Degradation starts with the cleavage of glycosidic bonds, together with the more labile polar groups. This process is followed by the breakdown of the C-C bonds in the carbon backbone between 300-350 1C, resulting in the formation of an organic residue.…”

“…When we recently reported on the conductivity of a chondroitin sulfate/ citric acid system, only a handful of papers dealing with this subject were cited. 47 This lack of information prompted us to dig deeper and realise that over the last 45 years, work concerning GAGs and conductivity has been published regularly, even if modestly, establishing a sort of undercurrent in the midst of all the work being done within the greater family of polysaccharides (Fig. 2).…”

An Internal Real-Time Microscopic Diagnosis of a Proton Battery Stack during Charging and Discharging

“…Because it has the smallest ion size and the lightest weight, it is almost better than all other cations [4]. Proton-conducting electrolytes are mainly used in batteries, proton exchange membrane fuel cells, supercapacitors, and photoelectrochemical and electrochromic devices [5,6]. This type of electrolyte is very useful for creating organized energy storage systems, and these electrolyte-based batteries have a longer battery life, higher performance, easier maintenance, and energy characteristics that can bear different stages of operation [7,8].…”

Flexible Nanocellulose/Lignosulfonates Ion-Conducting Separators for Polymer Electrolyte Fuel Cells

“…The demand for fully biobased ion-exchange membranes has already prompted the fabrication of, for example, ion-exchange membranes composed of chondroitin sulfate (a sulfated glycosaminoglycan) [ 13 ], cellulose nanocrystals obtained by acidic hydrolysis with sulfuric acid (a sulfated nanocellulose) [ 14 ], and fucoidan (a sulfated polysaccharide) combined with BNC [ 6 ]. In all these instances, the adsorption of water molecules assisted by the sulfate moieties produced paths for the structural diffusion of protons, which translated into separators with ionic conductivity.…”