Insights into the use of polyethylene oxide in energy storage/conversion devices: a critical review

Abstract

In this review, latest updates in the poly (ethylene oxide) based electrolytes are summarized. The ultimate goal of researchers globally is towards the development of free standing solid polymeric separator for energy storage devices. This single free standing solid polymeric separator may replace the liquid and separator (organic/Inorganic) used in existing efficient/smart energy technology. As an example polyethylene oxide (PEO) consist of an electron donor rich group which provides coordinating sites to the cation for migration. Owing to this exclusive structure PEO exhibits some remarkable properties such as; low glass transition temperature, excellent flexibility and ability to make complexation with various metal salts which are unattainable by another polymer host. Hence, the PEO is the most emerging candidate that have been examined or is currently under audition for application in energy storage devices. So, this review article first provides the detailed study of the PEO properties, characteristic of constituents of polymer electrolyte and suitable approaches for the modification of polymer electrolytes. Then, the synthesization and characterizations techniques are outlined. The structures, characteristics, and performance during charge-discharge of four types of electrolyte/separators which are Liquid, Plasticized, and dispersed/intercalated electrolyte are highlighted. The suitable ion transport mechanism proposed by researchers in different renowned group have been discussed for better understanding of the ion dynamics in such systems.Keywords: polyethylene oxide, constituents of polymer electrolytes, structural and microstructural properties, electrochemical properties summarizes the requirements for selection of electrolyte cum separator for efficient lithium-ion battery system [4].At, present, LIB is the ideal choice for the automotive sector by Companies including Tesla Inc. and Volkswagen AG due to ease of transportation, environmentally friendly, less cost [5]. Allied Market Research published a report entitled, "World Lithium-Ion Battery Market: Opportunities and Forecasts, 2015-2022" and the main point was that the global LIB market is expected to generate revenue of $46.21 billion by 2022, with a CAGR of 10.8% during the forecast period (2016)(2017)(2018)(2019)(2020)(2021)(2022). At a 37 percent revenue share, Li-ion is the battery of choice for portable devices and the electric vehicles. There are no other systems till now that threaten the market of LIB today [figure 2].Recently in 2017, John Goodenough, inventor of Li-ion battery has developed the first all-solid-state battery cells using sodium-or lithium-coated glass electrolyte and claimed that new battery cells have three times more energy density (1,200 charge-discharge cycles) in comparison to existing rechargeable batteries. He concluded that they store and transmit energy at temperatures (-20 o C to 60 o C) lower than traditional lithium-ion packs and can be made using globally abundant supplies of sodium. One advantage of this...

Effect of salt concentration on dielectric properties of Li-ion conducting blend polymer electrolytes

“…As it is well known that the high amorphous content is required to promote the faster migration of the ion which leads to high ionic conductivity. To further improve the ion dynamics and transport properties polymers were modified by cross-linking and blending approaches etc, [24][25][26][27][28]. The polymer blending seems more promising and adaptable approach to obtain the enhanced properties in a controlled manner.…”

PEO‐PVP‐NaIO4 Ion‐Conducting Polymer Electrolyte: Inspection for Ionic Space Charge Polarization and Charge Trapping

“…), is the ion‐conducting organic polymer poly(ethylene oxide) (PEO) . This polymer is non‐ionic and relatively weakly polar, but its simple structure, easy processing, flexibility and other specific properties are suitable for development of SPEs with high ionic conductivity, relatively higher than other solvating polymers . In particular, the sequential oxyethylene group: CH 2 CH 2 O, and the polar groups: O, H, CH, in the polymer chains can well dissolve the ionic salts .…”

“…In particular, the sequential oxyethylene group: CH 2 CH 2 O, and the polar groups: O, H, CH, in the polymer chains can well dissolve the ionic salts . The biocompatibility, flexibility, the electrochemical stability, and excellent mechanical properties make the PEO‐based salt‐complexed SPEs extremely interesting for flexible plastic electrochemical sensors (for gas sensing applications, biosensors, biomedical diagnostics, and monitoring), in membrane systems, in electrical engineering as a polar electrolytes, as well as for use in organic molecular electronics and mechatronics . Due to the current interest on Na + rechargeable batteries (environmentally friendly, non‐toxic, low cost, and earth abundant), diverse PEO‐based SPEs have been synthesized using NaX salts ( X = Cl, I, Br, ClO 4 … etc.)…”

“…[10,11] This polymer is nonionic and relatively weakly polar, but its simple structure, easy processing, flexibility and other specific properties are suitable for development of SPEs with high ionic conductivity, relatively higher than other solvating polymers. [12][13][14] In particular, the sequential oxyethylene group: ─CH 2 ─CH 2 ─O─, and the polar groups: ─O─, ─H─, ─C─H─, in the polymer chains can well dissolve the ionic salts. [7,15,16] The biocompatibility, flexibility, the electrochemical stability, and excellent mechanical properties make the PEObased salt-complexed SPEs extremely interesting for flexible plastic electrochemical sensors (for gas sensing applications, biosensors, biomedical diagnostics, and monitoring), [17,18] in membrane systems, in electrical engineering as a polar electrolytes, as well as for use in organic molecular electronics and mechatronics.…”

Tailoring the Structural, Morphological, Electrochemical, and Dielectric Properties of Solid Polymer Electrolyte

“…But the semi-crystalline nature of PEO results in lower ionic conductivity. It is well known that amorphous phase supports fast ion transport in case of polymer electrolytes [18]. The Sodium hexafluorophosphate (NaPF6) was chosen as salt to provide ions due to advantages, (i) weak interaction between cation and anion, (ii) large anion size, and (iii) greater salt dissociation, hence reduce the chance of ion pair formation [19][20][21].…”