A. L. Sharma

Polymer electrolytes for lithium ion batteries: a critical study

Polymer electrolytes (PEs) are an essential component being used in most energy storage/conversion devices. The present review article on a brief history, advantage, and their brief application of polymer electrolyte systems. It consists of a glimpse on liquid, gel, and solid polymer electrolyte and a contrast comparison concerning benefits/disadvantages among the three. The article started with a brief introduction of polymer electrolytes followed by their varieties and extreme uses. The role of host polymer matrix by taking numerous examples of polymer electrolyte published by the different renowned group of the concerned field has been explored. The criteria for selection of appropriate host polymer, salt, inorganic filler/clay, and aprotic solvents to be used in polymer electrolyte have been discussed in detail. The mostly used polymer, salt, solvents, and inorganic filler/clay list has been prepared in order to keep the data bank at one place for new researchers. This article comprises different methodologies for the preparation of polymer electrolyte films. The different self-proposed mechanisms (like VTF, WLF, free volume theory, dispersed/intercalated mechanisms, etc.) have been discussed in order to explain the lithium ion conduction in polymer electrolyte systems. A numerous characterization techniques and their resulting analysis have been summarized from the different published reports at one place for better awareness of the scientific community/reader of the area.

Relaxation behavior in clay-reinforced polymer nanocomposites

The effect of clay reinforcement on dielectric, conductivity, and mechanical relaxation behavior of a polymer clay nanocomposite film is reported. Polymer nanocomposite is composed of three component polymers (polyacrylonitrile) as a host matrix, salt (LiPF6) as conducting species, and clay (sodium montmorillonite) as intercalant. The macroscopic parameters like polymer glass transition temperature and available free mobile charge carriers have been analyzed properly using dynamic mechanical analysis and dielectric analysis. Dielectric analysis indicated distribution of relaxation time as a function of clay concentration, whereas conductivity spectrum exhibited dispersion at lower frequency followed by saturation region at intermediate frequency. The dispersion behavior is related to the electrode polarization attributed to faster ion dynamics. The dielectric and conductivity relaxation are in excellent correlation with mechanical relaxation owing to the changes in glass transition temperature due to polymer-ion-clay interaction. The proposed mechanism is a sequel to the experimental results.

Dielectric Study of Polymer Nanocomposite Films for Energy Storage Applications

In the present study we have a novel report on the types of dielectric studies of the two blend polymer consisting of polyacrylonitrile (PAN) as the host polymer-polyethylene oxide (PEO) as a copolymer, LiPF6 as lithium salts and clay containing different weight percent of DMMT as modified montmorillonite. The polymer nanocomposite (PNC) films were prepared by using solution cast technique. However the pure PAN-PEO+LiPF6 film was prepared as a reference. Keeping in view of characterization of PNCs films were study by impedance spectroscopy technique. The high frequency range of dielectric measurement is 1 Hz–1 MHz. This technique is shown to be a viable and straight forward means of obtaining dielectric data on polymer electrolytes. Permittivity (\({ \in }^{\prime }\)), dielectric loss (\({ \in }^{\prime \prime }\)) and a.c. conductivity variation with frequency was studied to estimate the relaxation times for PAN-PEO polymer electrolyte.

Sodium-ion-conducting polymer nanocomposite electrolyte of TiO2/PEO/PAN complexed with NaPF6

A free standing transparent film of solid state polymer electrolyte based on PEO/PAN+NaPF6 with different compositions of nano sized TiO2 in weight percent (x = 0, 1, 2, 5, 10, 15, 20) is synthesized by using standard solution cast technique. The homogeneous surface of above polymer composition is examined by FESEM. The microscopic interaction among polymer, salt and nanoceramic filler has been analyzed by Fourier Transformed Infra-Red (FTIR) spectroscopy. The reduction of ion pair formation in polymeric separator is clearly observed on addition of nanofiller in the polymer salt complex film. Electrical conductivity has been recorded of the prepared polymeric separator which is of the order of ∼10−4 Scm−1 after addition of nanofiller (15% wt/wt) which support the FTIR results. Electrochemical potential window has been observed of the order of ∼6V by the cyclic voltammetry results. The observed data of the prepared separator are at par with the desirable value for device applications

High ionic conductivity and desirable stability properties of PNC for renewable energy applications

Polymer nanocomposites (PNCs) are materials of considerable interest worldwide, as the excellent substitute for separator between electrode compartments in renewable energy conversion/storage devices such as; high energy density batteries, supercapacitors and PEM fuel cell. Solid polymeric ionic conductor as a separator is the ultimate substitute to eliminate the drawback related to liquid and gel polymer ionic conductors. As a consequence the practical realization of a light weight high energy density device comprising of all solid components still remains a challenge. Present work is devoted to the analysis and evaluation of stability (thermal, mechanical and voltage) properties of soft PNCs endowed with high ionic conductivity.

Development of Novel Cathode Materials Based on MWCNT for Energy Storage/Conversion Devices

In Chap. 1, already available technology for energy storage solutions like capacitors, lead acid batteries, compressed air energy storage, flywheels has been discussed in order to compare their energy and power densities. Emphasis has been laid on Rechargeable Lithium ion Battery (Li-ion). Various materials which are already explored and used as cathode of battery has also been discussed with their merits and demerits. Further introduction of prepared orthosilicate material with used conductive additive Multiwalled carbon nano tube (MWCNT) has also given. In Chap. 2, methodology used to prepare respective Li2MnFeSiO4 material and its composite with MWCNT has been discussed in detail. Further, in order to validate its electrochemical application, different steps of cell assembly of Lithium half cell fabrication has also been discussed. Chapter 3 comprises of results obtained using standard Field emission scanning electron microscope (FESEM). Effect of used MWCNT on its morphology has been discussed in this chapter. A.C Impedance spectroscopy has been used to study variation in conductivity with respect to bared material. Possible reasons for increased conductivity with morphology has also been discussed in discussion. Chapter 4 includes conclusions drawn from mentioned results. This chapter summarizes measured conductivity values with different concentrations of MWCNT. Improved conductivity with respect to bared orthosilicate material has been pointed in this chapter.

Correlation of Microscopic Interaction with Electrical Conductivity in Polymer Separator of Energy Storage Devices

In the present report solid polymer nanocomposite (PNCs) comprising of (PEO)14 + NaClO4 + wt% BaTiO3 has been prepared by solution casting method. Important characterization like: FTIR (Fourier Transform Infrared Spectroscopy), and conductivity have been performed for the applicability of the prepared materials in device application. The highest conductivity of the prepared polymer nanocomposite materials has been estimated 1×10−4 Scm−1 for 15 wt% of BaTiO3. A very fine correlation has been built among polymer-ion, ion-ion and polymer ion interaction with obtained conductivity results.

Structural and Electrical Properties of Polymer Nanocomposite Films

A free standing transparent film of solid state polymer electrolyte based on PEMA/PVC+NaPF6 with different compositions of nano sized TiO2 in weight percent (x = 0, 1, 2, 7, 10, 15, 20) is synthesized by using standard solution cast technique. The homogeneous surface of above polymer composition is examined by FESEM. The microscopic interaction among polymer, salt and nano-ceramic filler has been analyzed by Fourier Transformed Infra-Red (FTIR) spectroscopy. The reduction of ion pair formation in polymeric separator is clearly observed on addition of nano-filler in the polymer salt complex film. Electrical conductivity has been recorded of the prepared polymeric separator which is of the order of ~1.5 × 10−5Scm−1 after addition of nano-filler (15 % wt/wt) which support the FTIR results. Electrochemical potential window has been observed of the order of ~6 V by the cyclic voltammetry results. The observed data of the prepared separator are at par with the desirable value for device application.

Correlation of ion-ion interaction with electrical conductivity in solid state polymeric separator for energy storage applications

In the present study, we report innovative study on the prepared high quality solid state free standing thin polymeric separator. In prepared free standing polymeric separator, polymer (PEO) has been used as host matrix; appropriate bulky anion salt (LiPF6) as conducting species and Nano ceramic filler (BaTiO3) is used to enrich the mechanical and thermal stability of separator used for the device applications. The Fourier Transform Infra-Red (FTIR) result has been analysed properly of the prepared materials to look the microscopic interaction among polymer-ion, ion-ion and polymer-ion-clay interaction. Electrical conductivity results has been recorded using the impedance spectroscopy results which gives the estimated value of the order of ∼10−3 Scm−1 of the nano ceramic doped polymeric separator which is desirable for energy storage application. A fine correlation has been established between the obtained results by this two analysis.

Transport properties of plastic separator for renewable energy applications

We report innovative results on optimization of intercalated polymer-clay nanocomposite endowed with desirable properties; (i) very high ionic conductivity (∼10−3 S cm−1) at room temperature, (ii) tion∼99% and cation transport number (tLi+)∼67%: Intercalation of (PAN)8LiCF3SO3 complex into dodecylamine modified montmorillonite clay (DMMT) nanometric channels has been confirmed by Transmission electron microscopy (TEM) analysis. The optimized polymer film serves dual purpose of electrolyte and separator in energy storage devices.