High Performance Poly(vinyl alcohol)-Based Li-Ion Conducting Gel Polymer Electrolyte Films for Electric Double-Layer Capacitors

Abstract

With 1-methyl-2-pyrrolidinone (NMP) as the solvent, the biodegradable gel polymer electrolyte films are prepared based on poly(vinyl alcohol) (PVA), lithium bis(trifluoromethane)sulfonimide (LiTFSI), and 1-ethyl-3 methylimidazoliumbis(trifluoromethylsulfonyl)imide (EMITFSI) by means of solution casting. The films are characterized to evaluate their structural and electrochemical performance. The 60PVA-40LiTFSI + 10 wt.% EMITFSI system exhibits excellent mechanical properties and a high ionic transference number (0.995), indicating primary ionic conduction in the film. In addition, because of the flexibility of polymer chain segments, its relaxation time is as low as 5.30 × 10−7 s. Accordingly, a high ionic conductivity (3.6 × 10−3 S cm−1) and a wide electrochemical stability window (~5 V) are obtained. The electric double-layer capacitor (EDLC) based on this electrolyte system shows a specific capacitance of 101 F g−1 and an energy density of 10.3 W h kg−1, even after 1000 charge-discharge cycles at a current density of 0.4 A g−1 under a charging voltage of 2 V. All these excellent properties imply that the NMP-soluble 60PVA-40LiTFSI + 10 wt.% EMITFSI gel polymer electrolyte could be a promising electrolyte candidate for electrochemical device applications.

Glycerolized Li+ Ion Conducting Chitosan-Based Polymer Electrolyte for Energy Storage EDLC Device Applications with Relatively High Energy Density

“…The small value of ESR portrays good contact between the electrode and the electrolyte and indicates that it is easy for ions to migrate toward the surface of the electrode to form an electrical double-layer [73]. A similar trend is observed for the starch-lithium acetate system, where the ESR is slightly increased when the C s remains at a constant value [74]. Besides, the rapid charging and discharging process will lead to the recombination of free ions, and then the ion pair will be developed, which leads to the conductivity decrement.…”

Structural, Morphological, Electrical and Electrochemical Properties of PVA: CS-Based Proton-Conducting Polymer Blend Electrolytes

“…Comparably, in our earlier report on PVA:dextran:NH 4 I system, 1.3 V was obtained [70]. There is harmony between the potential window that is lower than 1 V and undesired consequences, such as solvent evaporation and leakage in supercapacitor systems [10]. Consequently, these results help to decide on the eligibility of PVA:CS:NH 4 I as the electrolyte of choice in EDLC applications.…”

“…PVA is mainly composed of vinyl alcohol groups (i.e., enriched with polar oxygen atoms) that can make complexes with the salt cations, thus forming polymer electrolyte complexes. Furthermore, PVA is characterized by several inherent properties, for instance, non-toxicity, affordability, a relatively high capacity of charge storage and exceptional mechanical properties [10,11]. The ability of PVA to form electrolytes is associated with its hydrophilic properties [12] and several hydroxyl groups attached to methane carbons (CH 2 -CH) on the PVA backbone [13].…”

The Study of Plasticized Amorphous Biopolymer Blend Electrolytes Based on Polyvinyl Alcohol (PVA): Chitosan with High Ion Conductivity for Energy Storage Electrical Double-Layer Capacitors (EDLC) Device Application

“…It can be seen that the E d value at the first cycle is 4.9 Wh/kg, and beyond it just about unchanged toward the 150th cycle with an average of ~4.8 Wh/kg (see Figure 10 a). This display implies the almost same energy barrier for the transportation of ions in the prepared electrolyte film, from the 1st to 150th cycle [ 89 ]. Pandey et al [ 88 ] have stated the energy density, E d of (0.3 Wh/kg) in their electrolyte system, which is worse than the current work.…”