Direct borohydride fuel cells: A selected review of their reaction mechanisms,electrocatalysts, and influence of operating parameters on their performance

Direct borohydride fuel cells (DBFC) oxidize an easily-stored energy-dense borohydride fuel (sodium borohydride: NaBH₄), that in theory reacts ca. 400 mV below H₂ and produces 8 electrons per BH₄^- anion. However, the borohydride oxidation reaction (BOR) does not fully meet these promises in practice: the electrocatalyst nature, structure and state-of-surface, and the operating conditions (pH, BH₄^- concentration, temperature, fluxes) noticeably influence the BOR kinetics and mechanism. Nickel and platinum-based catalysts both have assets for the BOR. DBFCs can only yield decent performance if their separator combines high ion-conductivity and efficient separation of the reactants; cation-exchange membranes, anion-exchange membranes, bipolar membranes and porous separators all have their own advantages and drawbacks. Besides the anode, the choice of separator must consider the DBFC cathode reaction, where oxygen (usually from air) or hydrogen peroxide are reduced, provided adapted catalysts are used. All these aspects drive the DBFC performance and stability/durability.     

Hydrogen/oxygen polymer electrolyte membrane fuel cells (PEMFCs) based on alkaline-doped polybenzimidazole (PBI)

When complexed with alkaline such as potassium hydroxide, sodium hydroxide or lithium hydroxide, films (40 μm thick) of polybenzimidazole (PBI) show conductivity in the 5 × 10⁻⁵–10⁻¹ S/cm⁻¹ range, depending on the type of alkali, the time of immersion in the corresponding base bath and the temperature of immersion. It has been shown that PBI has a remarkable capacity to concentrate KOH, even in an alkaline bath of concentration 3 M. The highest conductivity of KOH-doped PBI (9×10⁻² S cm⁻¹) at 25°C obtained in this work is higher than the we had obtained previously as optimum values for H₂SO₄-doped PBI (5 × 10⁻² S cm⁻¹ at 25°C) and H₃PO₄-doped PBI ( 2 × 10⁻³ S cm⁻¹ at 25°C). PEMFCs based on an alkali-doped PBI membrane were demonstrated, and their characteristics exhibited the same performance as those of PEMFCs based on Nafion® 117. Their development is currently under active investigation.     

Thermal studies of potassium tetrahydroborate−sodium tetrafluoroborate mixtures

The KBH₄?NaBF₄ mixture was studied by thermal analysis (differential scanning calorimetry). Chemical analysis, X-ray powder diffraction analysis, IR spectroscopy, and ¹¹B and ¹⁹F MAS NMR spectroscopy showed that the primary stage of the complex pyrolysis process is a metathesis reaction between components to form a new mixture, NaBH₄?KBF₄, the decomposition of which with the release of gaseous products and the formation of polyhedral borohydride compounds (mainly B₁₂H₁₂ ^2-) in the solid residue begins at a temperature of about 563 K. At a certain ratio between reactants in the initial mixture KBH₄?NaBF₄, the B₁₂H₁₂ ^2- anion can form with the material participation of the BF₄ ^- anion.     

Highly Elastic Slide-Ring Hydrogel with Good Recovery as Stretchable Supercapacitor

As a new material with excellent mechanical properties and good stability, slide-ring gels have attracted attention and research. However, they cannot be widely used due to their relatively complicated synthesis. Herein, we use 6-acrylamidomethylether-modified α-cyclodextrin (αCDAAmMe) and PEG₂₀₀₀₀ diacrylate (PEG₂₀₀₀₀DA) to construct a polypseudorotaxane. Then, the polypseudorotaxane reacts with acrylamide via a photo-initiated polymerization in situ to conveniently obtain a slide-ring hydrogel with good elastic property and high recovery property. The hydrogel can be easily stretched to 22.5 times of its original length but recovered rapidly and almost reversibly. These results enable the application of hydrogel to make an intrinsically stretchable and compressible supercapacitor after doping ions and the adhesion of commercially available carbon nanotube (CNT) paper as electrodes, giving the ionic conductivity of 17.0 mS cm⁻¹ (comparable to that of the commercial PVA/H₃PO₄ electrolyte) and the capacitance of 0.87 μF cm⁻² (at the scan speed of 100 mV s⁻¹), and its capacitance can be further enhanced under stretching.     

Comparison of the properties of waterborne polyurethane/multiwalled carbon nanotube and acid‐treated multiwalled carbon nanotube composites prepared by in situ polymerization

A series of waterborne polyurethane (WBPU)/multiwalled carbon nanotube (CNT) and WBPU/nitric acid treated multiwalled carbon nanotube (A‐CNT) composites were prepared by in situ polymerization in an aqueous medium. The optimum nitric acid treatment time was about 0.5 h. The effects of the CNT and A‐CNT contents on the dynamic mechanical thermal properties, mechanical properties, hardness, electrical conductivity, and antistatic properties of the two kinds of composites were compared. The tensile strength and modulus, the glass‐transition temperatures of the soft and hard segments (T_gs and T_gh, respectively), and ΔT_g (T_gh − T_gs) of WBPU for both composites increased with increasing CNT and A‐CNT contents. However, these properties of the WBPU/A‐CNT composites were higher than those of the WBPU/CNT composites with the same CNT content. The electrical conductivities of the WBPU/CNT1.5 and WBPU/A‐CNT1.5 composites containing 1.5 wt % CNTs (8.0 × 10⁻⁴ and 1.1 × 10⁻³ S/cm) were nearly 8 and 9 orders of magnitude higher than that of WBPU (2.5 × 10⁻¹² S/cm), respectively. The half‐life of the electrostatic charge (τ_1/2) values of the WBPU/CNT0.1 and WBPU/A‐CNT0.1 composites containing 0.1 wt % CNTs were below 10 s, and the composites had good antistatic properties. From these results, A‐CNT was found to be a better reinforcer than CNT. These results suggest that WBPU/A‐CNT composites prepared by in situ polymerization have high potential as new materials for waterborne coatings with good physical, antistatic, and conductive properties. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3973–3985, 2005     

Understanding anion transport in an aminated trimethyl polyphenylene with high anionic conductivity

An alkaline exchange membrane (AEM) based on an aminated trimethyl poly(phenylene) is studied in detail. This article reports hydroxide ion conductivity through an in situ method that allows for a more accurate measurement. The ionic conductivities of the membrane in bromide and carbonate forms at 90 °C and 95% RH are found to be 13 and 17 mS cm⁻¹ respectively. When exchanged with hydroxide, conductivity improved to 86 mS cm⁻¹ under the same experimental conditions. The effect of relative humidity on water uptake and the SAXS patterns of the AEM membranes were investigated. SAXS analysis revealed a rigid aromatic structure of the AEM membrane with no microphase separation. The synthesized AEM is shown to be mechanically stable as seen from the water uptake and SAXS studies. Diffusion NMR studies demonstrated a steady state long-range diffusion constant, D_∞ of 9.8 × 10⁻⁶ cm² s⁻¹ after 50–100 ms. © 2012 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1743–1750, 2013     

Hydrogen storage in borohydrides Comparison of hydrolysis conditions of LiBH<Subscript>4</Subscript>, NaBH<Subscript>4</Subscript> and KBH<Subscript>4</Subscript>

The hydrogen storage capabilities of alkaline borohydrides through a hydrolyzing process were determined by taking into consideration the hydration of the end products. Comparison of LiBH₄, NaBH₄ and KBH₄ showed their storage capacities to be dependent on the composition of the metaborate formed. This composition is ruled by the hydrolysis conditions, especially the temperature reached during the reaction and the stability of the hydrates. The borohydride with the highest hydrogen content in the solid state, LiBH₄, could be less efficient than KBH₄ if the hydrolysis is performed at 120°C.     

Enhanced Energy Density of Coaxial Fiber Asymmetric Supercapacitor Based on MoS2@Fe2O3/Carbon Nanotube Paper and Ni(OH)2@NiCo2O4/Carbon Nanotube Fiber Electrodes

Fiber supercapacitors are promising energy storage devices for potential application in wearable and miniaturized portable electronics, which currently suffer from difficulties in achieving high capacitance and energy density synchronously owing to the limited specific surface area of the electrode materials and material incompatibility between the two electrodes. Herein, a strategy is developed for the manufacture of coaxial asymmetric fiber supercapacitors by wrapping a core of PVA-KOH gel electrolyte-coated Ni(OH)₂@NiCo₂O₄/CNT fibers with MoS₂@Fe₂O₃/CNT paper. The as-prepared coaxial fiber asymmetric supercapacitors exhibit a specific capacitance of 373 mF cm⁻² (at a current density of 2 mA cm⁻²) and energy density of 0.13 mW h cm⁻² (at a power density of 3.2 mW cm⁻²), and also show good rate capability, long cycle life, and excellent flexibility. This work provides the possibility for the practical application of fiber supercapacitors in wearable and portable energy storage equipment.     

Highly proton conducting proton‐exchange membranes based on fluorinated poly(arylene ether ketone)s with octasulfonated segments

A new bisphenol monomer containing a pair of electron‐rich tetra‐arylmethane units was designed and synthesized. Based on this monomer, along with commercial 4,4′‐(hexafluoroisopropylidene)diphenol A and 4,4′‐difluorobenzophenone, a series of novel poly(arylene ether ketone)s containing octasulfonated segments of varying molar percentage (x) (6F‐SPAEK‐x) were successfully synthesized by polycondensation reactions, followed by sulfonation. Tough, flexible, and transparent membranes, exhibiting excellent thermal stabilities and mechanical properties were obtained by casting. 6F‐SPAEK‐x samples exhibited appropriate water uptake and swelling ratios at moderate ion exchange capacities (IECs) and excellent proton conductivities. The highest proton conductivity (215 mS cm⁻¹) is observed for hydrated 6F‐SPAEK‐15 (IEC = 1.68 meq g⁻¹) at 100 °C, which is more than 1.5 times that of Nafion 117. Furthermore, the 6F‐SPAEK‐10 membrane exhibited comparable proton conductivity (102 mS cm⁻¹) to that of Nafion 117 at 80 °C, with a relatively low IEC value (1.26 meq g⁻¹). Even under 30% relative humidity, the 6F‐SPAEK‐20 membrane (2.06 meq g⁻¹) showed adequate conductivity (2.1 mS cm⁻¹) compared with Nafion 117 (3.4 mS cm⁻¹). The excellent comprehensive properties of these membranes are attributed to well‐defined nanophase‐separated structures promoted by strong polarity differences between highly ionized and fluorinated hydrophobic segments. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 25–37     

Electro‐optical properties of electropolymerized poly(3‐hexylthiophene)/carbon nanotube composite thin films

3‐hexylthiophene was electropolymerized on a carbon nanotube (CNT)‐laden fluorine‐doped tin oxide substrate. Scanning electron microscopy and Raman spectroscopy revealed that the polymer was infused throughout the thickness of the 150‐nm thick CNT mat, resulting in a conducting composite film with a dense CNT network. The electropolymerized poly(3‐hexylthiophene) (e‐P3HT)/CNT composites exhibited photoluminescence intensity quenching by as much as 92% compared to the neat e‐P3HT, which provided evidence of charge transfer from the polymer phase to the CNT phase. Through‐film impedance and J‐V measurements of the composites gave a conductivity (σ) of 1.2 × 10^?10 S cm^?1 and zero‐field mobility (μ₀) of 8.5 × 10^?4 cm² V^?1 s^?1, both of which were higher than those of neat e‐P3HT films (σ = 9.9 × 10^?12 S cm^?1, μ₀ = 3 × 10^?5 cm² V^?1 s^?1). In electropolymerized samples, the thiophene rings were oriented in the (010) direction (thiophene rings parallel to substrate), which resulted in a broader optical absorbance than for spin coated samples, however, the lack of long‐range conjugation caused a blueshift in the absorbance maximum from 523 nm for unannealed regioregular P3HT (rr‐P3HT) to 470 nm for e‐P3HT. Raman spectroscopy revealed that π‐π stacking in e‐P3HT was comparable to that in rr‐P3HT and significantly higher than in regiorandom P3HT (ran‐P3HT) as shown by the principal Raman peak shift from 1444 to 1446 cm^?1 for e‐P3HT and rr‐P3HT to 1473 cm^?1 for ran‐P3HT. This work demonstrates that these polymer/CNT composites may have interesting properties for electro‐optical applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1269–1275, 2011     

Chemoselective Reduction of Diaryl Bisulfides to Thiols with Sodium Borohydride in Mixed Solvent Containing Methaxol

Sodium borohydride(NaBH₄) is a readily available, mild reducing agent and is easy to manipulate.¹ On the other hand, reduction of disulfide to the corresponding thiol is an important reaction both in bio- and organic chemistry.² However, disulfides can't be reduced by NaBH₄ except those of limited structures³ such as lipoic acid.     

Hybrid Transition-Metal Oxide and Nitride@N-Doped Reduced Graphene Oxide Electrodes for High-Performance,Flexible, and All-Solid-State Supercapacitors

Nanoscale composites for high-performance electrodes employed in flexible, all-solid-state supercapacitors are being developed. A series of binder-free composites, each consisting of a transition bimetal oxide, a metal oxide, and a metal nitride grown on N-doped reduced graphene oxide (rGO)-wrapped nickel foam are obtained by using a universal strategy. Three different transition metals, Co, Mo, and Fe, are separately compounded with nickel ions, which originate from the nickel foam, to form three composites, NiCoO₂@Co₃O₄@Co₂N, NiMoO₄@MoO₃@Mo₂N, and NiFe₂O₄@Fe₃O₄@Fe₂N, respectively. These as-prepared active materials have similar regular variation patterns in their properties, including better conductivity and battery-mimicking pseudocapacitance, which result in their high whole-electrode capacitance performance [2598.3 F g⁻¹ (39.85 F cm⁻²), 3472.6 F g⁻¹ (41.43 F cm⁻²) and 1907.5 F g⁻¹ (3.41 F cm⁻²) for the composites incorporating Co, Mo, and Fe, respectively]. The as-assembled flexible, all-solid-state NiCoO₂@Co₃O₄@Co₂N//KOH/PVA//NiCoO₂@Co₃O₄@Co₂N device can be easily bent and exhibits high energy density and power density of 92.8 Wh kg⁻¹ and 1670.4 W kg⁻¹, respectively. The universality of this design strategy could allow it to be employed in producing hybrid materials for high-performance energy-storage devices.     

Blends of polyester having amino sulfonic acid moieties with poly(vinyl alcohol) and their metal complex formation

Polyester having amino sulfonic acid moieties (TBES) was prepared by a liquid/solid biphase polycondensation of terephthaloyl chloride (TPC) and N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES) in trimethyl phosphate (TMP) using triethylamine (TEA) as an acid acceptor. Blends of TBES with PVA and their metal complexes with Ni²⁺ and Co²⁺ ions were prepared. A strong interaction was observed between TBES and PVA. An electric conductivity of 10⁻⁶ S cm⁻¹ was attained for the blend films containing about 5 wt % water. A coordination structure with two chelate rings is proposed for the metal complex with Ni²⁺ and Co²⁺ ions when the molar ratio of amino sulfonic acid groups in TBES to metal ions is larger than 2. Polymer blends complexed with Ni²⁺ or Co²⁺ ions result in semi-interpenetrating polymer networks from chelate formation. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3561–3569, 1997     

Synthesis of amorphous manganese borohydride in the(NaBH_4–MnCl_2) system,its hydrogen generation properties and crystalline transformation during solvent extraction

The mixture of(2NaBH_4+ MnCl_2) was ball milled in a magneto-mill. No gas release was detected. The XRD patterns of the ball milled mixture exhibit only the Bragg diffraction peaks of the Na Cl-type salt which on the basis of the present X-ray diffraction results and the literature is likely to be a solid solution Na(Cl)x(BH4)(1-x), possessing a cubic Na Cl-type crystalline structure. No presence of any crystalline hydride was detected by powder X-ray diffraction which clearly shows that NaBH_4 in the initial mixture must have reacted with MnCl_2 forming a Na Cl-type by-product and another hydride that does not exhibit X-ray Bragg diffraction peaks. Mass spectrometry(MS) of gas released from the ball milled mixture during combined MS/thermogravimetric analysis(TGA)/differential scanning calorimetry(DSC) experiments, confirms mainly hydrogen(H2) with a small quantity of diborane gas, B_2H_6. The Fourier transform infra-red(FT-IR) spectrum of the ball milled(2NaBH_4+ MnCl_2) is quite similar to the FT-IR spectrum of crystalline manganese borohydride, c-Mn(BH_4)_2, synthesized by ball milling, which strongly suggests that the amorphous hydride mechano-chemically synthesized during ball milling could be an amorphous manganese borohydride. Remarkably, the process of solvent filtration and extraction at 42 °C, resulted in the transformation of mechano-chemically synthesized amorphous manganese borohydride to a nanostructured,crystalline, c-Mn(BH_4)_2hydride.     

Polymerized ionic liquids: Effects of counter‐anions on ion conduction and polymerization kinetics

A novel imidazolium‐containing monomer, 1‐[ω‐methacryloyloxydecyl]‐3‐(n‐butyl)‐imidazolium (1BDIMA), was synthesized and polymerized using free radical and controlled free radical polymerization followed by post‐polymerization ion exchange with bromide (Br), tetrafluoroborate (BF₄), hexafluorophosphate (PF₆), or bis(trifluoromethylsulfonyl)imide (Tf₂N). The thermal properties and ionic conductivity of the polymers showed a strong dependence on the counter‐ions and had glass transition temperatures (T_g) and ion conductivities at room temperature ranging from 10 °C to −42 °C and 2.09 × 10⁻⁷ S cm⁻¹ to 2.45 × 10⁻⁵ S cm⁻¹. In particular, PILs with Tf₂N counter‐ions showed excellent ion conductivity of 2.45 × 10⁻⁵ S cm⁻¹ at room temperature without additional ionic liquids (ILs) being added to the system, making them suitable for further study as electro‐responsive materials. In addition to the counter‐ions, solvent was found to have a significant effect on the reversible addition‐fragmentation chain‐transfer polymerization (RAFT) for 1BDIMA with different counter‐ions. For example, 1BDIMATf₂N would not polymerize in acetonitrile (MeCN) at 65 °C and only achieved low monomer conversion (< 5%) at 75 °C. However, 1BDIMA‐Tf₂N proceeded to high conversion in dimethylformamide (DMF) at 65 °C and 1BDIMABr polymerized significantly faster in DMF compared to MeCN. NMR diffusometry was used to investigate the kinetic differences by probing the diffusion coefficients for each monomer and counter‐ion in MeCN and DMF. These results indicate that the reaction rates are not diffusion limited, and point to a need for deeper understanding of the role electrostatics plays in the kinetics of free radical polymerizations. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1346–1357     

Study of carbonaceous clusters in irradiated polycarbonate with UV–vis spectroscopy

The formation of carbonaceous clusters in ion‐irradiated polymer films was investigated extensively. Information about these clusters may be obtained with ultraviolet–visible (UV–vis) spectroscopy. The optical band gap (E_g), calculated from the absorption edge of the UV spectra of these polymers, can be correlated to the number of carbon atoms (N) in a cluster with the modified Tauc equation. The structure of the cluster is also related to E_g; for example, a six‐membered‐benzene‐ring‐type structure has an E_g of ≈5.3 eV, whereas a buckminsterfullerene‐type structure has an E_g of ≈4.9 eV. These clusters are responsible for the electrical conductivity in these films. In this work, polycarbonate films (20 μm thick) were irradiated with 45‐MeV Li ions at fluences of 1 × 10¹² to 1 × 10¹³ cm⁻² and were characterized with UV–vis spectroscopy and impedance measurements. The E_g values, calculated from the absorption edge in the 280–315‐nm region with the Tauc relation, varied from 4.39 to 4.35 eV for the pristine and various irradiated samples, respectively. The cluster size showed a range of 60–62 carbon atoms per cluster. The sheet conductivity (σ_dc) and loss (tan δ) values of 10⁻¹⁶ Ω⁻¹cm⁻¹ and 10⁻³ for the pristine sample changed to 10⁻¹⁵ Ω⁻¹cm⁻¹ and 10⁻², respectively, for the irradiated samples. This increase in the values of σ_dc and tan δ may be correlated to the increase in the size of the carbonaceous clusters. This study provides insight into the mechanism of electrical conductivity in irradiated polymers. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1589–1594, 2000     

Core-shell microgel stabilized silver nanoparticles for catalytic reduction of aryl nitro compounds

Silver nanoparticles loaded into shell of poly (styrene-N-isopropylmethacrylamide-co-acrylic acid) core shell [P (SNA-CS)] gel particles were synthesized and analyzed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), ultraviolet–visible spectroscopy (UV–vis) and dynamic light scattering (DLS). Catalytic activity of Ag@P (SNA-CS) particles was investigated by reducing p-nitroaniline (p-NA) into p-aminoaniline (p-AA) in the presence of sodium borohydride (NaBH₄) reductant. Molecules of the substrate adsorbed on the surface of silver nanoparticles interact with borohydride ions (BH₄⁻) to form p-AA. Other nitroarenes like o-nitroaniline (o-NA), p-nitrophenol (p-NP) o-nitrophenol (o-NP), 2,4-dinitrophenol(2,4-DNP) were also reduced into their corresponding aryl amines using Ag@P (SNA-CS) composite microgels as catalyst. Reported catalyst efficiently reduced the nitro aromatic compounds individually as well as simultaneously at ambient temperature. Effect of different reaction conditions (catalyst dose, concentration of NaBH₄ and concentration of p-NA) on reaction completion time, value of apparent rate constant (k_app) and reduction efficiency of the catalyst for reduction of p-NA was also demonstrated. Ag@P (SNA-CS) catalyst was found to be able to retain activity up to four cycles.     

Synthesis of a novel highly conjugated conducting polymer

The new conjugated polyacetylene derivative dehydrated poly(4-hydroxy-4-phenyl-1-butyne) [dehydrated poly(HPB)] was synthesized from poly(4-hydroxy-4-phenyl-1-butyne) [poly(HPB)], which was obtained by the polymerization of 4-hydroxy-4-phenyl-1-butyne. The resulting dehydrated poly(HPB) was soluble in common organic solvents. The dehydrated poly(HPB) was found to have extended conjugated polyene structure. The dehydrated poly(HPB) was thermally stable up to 300°C. The electrical conductivity of I₂-doped dehydrated poly(HPB) was 10⁻² S cm⁻¹. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 949–953, 1998     

Formation of poly(vinyl alcohol)–iodine complexes in solution

The effect of the dissolved state of poly(vinyl alcohol) (PVA) molecules in water on the color development due to PVA–iodine complexes was investigated at each given PVA and iodine concentration using two kinds of syndiotactic-rich PVA (S-PVA) which are unstable in water because of the formation of intermolecular hydrogen bonds and form the complex easily. In the reaction mixtures prepared by mixing PVA solutions and an iodine solution, the color development was constant and independent of standing time of the PVA solution before the addition of iodine up to a certain time, after which it decreased with the standing time. The color development obtained with use of the PVA solution allowed to stand for a fixed time was higher for S-PVA with a lower s-(diad)%. In the case of the reaction mixture prepared by dissolving PVA in an iodine solution, the color development was higher for S-PVA with a higher s-(diad)%. The initial ratio of the I₅⁻/I₃⁻ and the rate of decrease in the ratio of I₅⁻/I₃⁻ were larger than those in the preceding case. The color development decreased for the PVA with an s-(diad) % of 58, whereas it increased for the PVA an s-(diad) % of 61.3 with increasing propanol content, an inhibitor of gelation. From these results, the aggregates of PVA molecules have been assumed to play an important role in forming the complexes. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1701–1709, 1997     

Characteristics of proton conducting polymer electrolyte based on chitosan acetate complexed with CH3COONH4

The polymer electrolytes based on chitosan and ammonium acetate (CH₃COONH₄) were prepared by solution casting technique and the properties were studied. With the addition of CH₃COONH₄, the amorphous nature of the polymer electrolytes was promoted. The glass transition temperature, activation energy, and conductivity are closely related. Lower the glass transition temperature, lower the activation energy, higher the conductivity. The 40 wt % ammonium acetate doped polymer electrolyte has the lowest glass transition temperature of 369 K, the lowest activation energy of 0.19 eV, and the highest ionic conductivity of 2.87 × 10^?4 S cm^?1 at room temperature. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 549–554, 2009