The recent discovery that metal-free polyterthiophene (PTTh) prepared by iodine-vapor-assisted polymerization (IVP) can catalyze the hydrogen evolution reaction (HER) when illuminated, and this light-enhanced electrolysis expresses a non-Nernstian relation with pH, provides the foundation for further improvement of the photovoltage of the reaction by engineering the band structure of the light-absorbing polymer. Deviating from an all-thiophene backbone, using poly(1,4-di(2-thienyl))benzene (PDTB) lowers the highest occupied molecular orbital level by approximate to 0.3 eV compared with polythiophene, and PDTB simultaneously maintains the photoelectrocatalytic properties without an all-thiophene backbone, resulting in very high conversion rate of 600 mmol(H-2) h(-1) g(-1) at 0 V versus the reversible hydrogen electrode (RHE) at pH 11. PDTB shows the same non-Nernstian behavior as PTTh with increasing onset potential (versus RHE) at higher pH, and the open circuit potential on PDTB under visible light reaches 1.4 V versus RHE at pH 12. The PDTB photocathode thus produces a photovoltage above the theoretical potential for the complete water-splitting (1.229 V) and is indeed able to produce hydrogen in a one-photon-per-electron light-driven water splitting setup with MnOx as the anode at a rate of 6.4 mmol h(-1) g(PDTB)(-1).

Polar groups and the charge-transport capability play significant roles in the dielectric properties of organic polymers, and thus influence the electric energy density upon application as a capacitor material. Here, the dielectric properties and electric conductivity of a series of polymers containing 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radicals are investigated. The neat radical polymer poly(TEMPO methacrylate) (PTMA) has a high dielectric constant but poor breakdown strength. Poly(methyl methacrylate) (PMMA) is introduced as an insulating polymer with high resistivity on breakdown, along with molecular design of PTMA. Copolymers of TEMPO methacrylate and methyl methacrylate, P(TMA-r-MMA), exhibit high breakdown strengths but low dielectric constants. PMMA blended with TEMPO exhibits the highest electric energy density of 7.4 J cm(-3) (that of PTMA is 0.48 J cm(-3) as a control), with both a high dielectric constant (approximate to 6.8) and a high breakdown strength (approximate to 500 MV m(-1)). It benefits from long-range but not bulk charge transport in the blends, which is different from the bulk charge transport in PTMA and the short-range charge transport in P(TMA-r-MMA). These results indicate that the TEMPO moiety located in the high breakdown matrix leads to a high energy-storage density in the capacitor.

We report the use of polyterthiophenes (PTTh) as a rare, combined light-harvester and catalyst for the hydrogen evolution reaction at high pH. Illuminated PTTh in combination with a MnOx anode in a two-electrode setup exhibited stable water-splitting at a bias-potential of only 0.3 V at pH 12. This confirms that PTTh used as photocathode can produce photovoltages of at least 900 mV for the hydrogen evolution reaction at high pH and is therefore a suitable match for traditional water-oxidation catalysts such as MnOx, CoOx, and RuOx. Films of PTTh were fabricated using a novel, metal-free method where iodine vapor is used as oxidant; thus, previously observed interference from metal residuals was omitted and thereby a gravimetric photo electrocatalytic conversion rate of 330 mmol(H-2) h(-1) g(-1) was achieved in phosphate buffer (pH 7) at 0 V vs. RHE. A striking property of this new strand of polythiophene was an "inverse" correlation (compared to that predicted using the Nernstian relationship) between the onset potential for the light-assisted water reduction reaction and pH: the potential (vs. RHE) required for a given current was more positive at higher pH, which is not observed for other (photo-) electrocatalytic materials, and indicates that the charge neutralization of PTTh (rather than the pH) guides the onset potential.

An ambient-light-promoted and,metal-free three-component reaction of active methylene compounds perfluoroalkyl iodides, and guanidines/amidines is reported: This constitutes a powerful method to prepare prfluoroalky-lated pyrinudines with mild reaction Conditions, broad substrate scope, excellent functional group tolerance, and simple operation. A radical/polar mechanism involving the formation of a halogen-bond adduct and radical cross-coupling is proposed.

To, design new and better organic active battery materials in a rational fashion, fundamental parameters of the charge transport must be studied. Herein we report on the electronic conductivity by electron diffusion in a TEMPO-containing redox polymer, and the reorganization energy of the TEMPO self exchange in an organic solvent is determined for the first time. The electronic conductivity was 8.5 mu S/cm at E-0 and corresponded to a redox hopping mechanism. The apparent electron diffusion coefficient was 1.9 x 10(-9) cm(2)/s at room temperature, and at short times the ion diffusion was limiting with a diffusion coefficient of 6.5 x 10(-10) cm(2)/s. The reorganization energy was determined to be 1.01 eV, indicating a rather polar chemical environment for the TEMPO groups. The implications for the usage of this type of materials in organic energy storage are discussed. As conductivity through 10 gm was demonstrated, we show that, if sufficient swellability can be ensured) charge can be transported through several micrometer thick layers in a battery electrode without any conducting additive.

Understanding the reaction distributions inside a polymer electrolyte fuel cell (PEFC) is essential for the higher performance and durability. We have developed a new see-through cell and visualized the distributions of oxygen partial pressure and current density inside a running PEFC at the temperature of 40 and 80 degrees C and the relative humidity of 53%. The oxygen utilization was changed from 0% to 80% by changing the current density. At higher oxygen utilizations, the current density was higher and therefore the water generation. Generated water droplets in the flow channel were also visualized, allowing for the simultaneous visualization of the distribution of the oxygen partial pressure, current density, and water droplets. By combining the observations of all three parameters, the reactions inside a membrane electrode assembly were discussed. (C) 2017 Elsevier B.V. All rights reserved.

Strong interchain interactions render unsubstituted polythiophene un-fusible, non-melting, and insoluble. Therefore, control of the packing structure, which has a profound effect on the optical and electronic properties of the polymer, has never been achieved. Unsubstituted polythiophene was prepared in the one-dimensional channels of [La(1,3,5-benzenetrisbenzoate)](n), where polymer chains form unprecedented assembly structures mediated by the host framework. It is noteworthy that the emission and carrier transport properties were drastically changed by varying the number of chains within a particular assembly. The response of the composite to additional guests is also examined as a method to use the composites as low-concentration sensors. Our findings show that the encapsulation of polymer chains in host materials is a facile method for understanding the intrinsic properties of conjugated polymers, along with controlling and enhancing their functions.

Reversible addition-fragmentation chain transfer polymerization yields reactive block copolymers bearing the pentafluorophenyl ester (PFPA) group, and subsequent Click amidation using 2,2,6,6-tetramethylpiperidine-N-oxyl- and imidazolium-functionalized primary amines produces the corresponding functional block copolymers, leading to installation of statistical radical-and ionic sites into the PFPA segment. The monolayered thin film devices fabricated using the obtained block copolymers exhibit repeatable switching of electric conductivity (on/off ratio > 10(3)) under a bias voltage, which reveals that the coexistence of radicals and ions in the same spherical domain of the copolymer layer is a prerequisite for repeatable switching memory.

Visualization of the oxygen partial pressure (p(O(2))) was performed at the surface of a gas diffusion layer (GDL) and the upper part of the gas-flow channel of the cathode of an operating polymer electrolyte fuel cell (PEFC) with straight flow channels by using an oxygen-sensitive luminescent dye film. The gradient of p(O(2)) inside a channel was clearly observed, even on the GDL surface across the channel. A numerical simulation was performed to understand the reaction distributions inside the PEFC. By visualization and numerical simulation, the distributions of p(O(2)), the current density, water concentration, and temperature in the operating PEFC were obtained, and the relationships between the parameters were studied. Supersaturated water inside the cell was found both experimentally and computationally. p(O(2)) and the water concentration were concluded to be the two most important factors in determining the distribution of power generation.

Visualization of the oxygen partial pressure (p(O(2))) was performed at the surface of a gas diffusion layer (GDL) and the upper part of the gas-flow channel of the cathode of an operating polymer electrolyte fuel cell (PEFC) with straight flow channels by using an oxygen-sensitive luminescent dye film. The gradient of p(O(2)) inside a channel was clearly observed, even on the GDL surface across the channel. A numerical simulation was performed to understand the reaction distributions inside the PEFC. By visualization and numerical simulation, the distributions of p(O(2)), the current density, water concentration, and temperature in the operating PEFC were obtained, and the relationships between the parameters were studied. Supersaturated water inside the cell was found both experimentally and computationally. p(O(2)) and the water concentration were concluded to be the two most important factors in determining the distribution of power generation.

The integration of functional components such as metal nanoparticles, metal salts, or ionic liquids with well-defined block copolymer (BCP) nanotemplates via non-covalent bond interactions has afforded hybrid functional materials. Here, we designed an ionic liquid (IL)-functionalized redox-active TEMPO (2,2,6,6-tetramethylpiperidine-N-oxy) radical (guest), investigated phase-selective incorporation/placement into host BCP nanostructured matrices, and established a rational approach to functionalize BCP templates. On-demand domain functionalization of poly(styrene-b-ethyl-ene oxide) (PS-b-PEO) was triggered by ion-ionophore interaction, as verified by the suppression of PEO melting transition in DSC, and the swelling behavior of the PEO spherical domain in AFM, TEM, and X-ray scattering characterizations. The obtained BCP layer containing the redox-active TEMPO and IL was utilized as an active layer in the diode-structured memory device, which exhibited on/off resistive switching (on/off ratio >10(3)). Systematic placement of TEMPO and IL in the BCP spherical domain allowed for tuning of the switching characteristics and revealed that the formation of a discontinuous redox-active domain was critical for rewritable resistive switching.

The integration of functional components such as metal nanoparticles, metal salts, or ionic liquids with well-defined block copolymer (BCP) nanotemplates via non-covalent bond interactions has afforded hybrid functional materials. Here, we designed an ionic liquid (IL)-functionalized redox-active TEMPO (2,2,6,6-tetramethylpiperidine-N-oxy) radical (guest), investigated phase-selective incorporation/placement into host BCP nanostructured matrices, and established a rational approach to functionalize BCP templates. On-demand domain functionalization of poly(styrene-b-ethyl-ene oxide) (PS-b-PEO) was triggered by ion-ionophore interaction, as verified by the suppression of PEO melting transition in DSC, and the swelling behavior of the PEO spherical domain in AFM, TEM, and X-ray scattering characterizations. The obtained BCP layer containing the redox-active TEMPO and IL was utilized as an active layer in the diode-structured memory device, which exhibited on/off resistive switching (on/off ratio >10(3)). Systematic placement of TEMPO and IL in the BCP spherical domain allowed for tuning of the switching characteristics and revealed that the formation of a discontinuous redox-active domain was critical for rewritable resistive switching.

© The Royal Society of Chemistry 2015. The topochemical conversion of a dense, insulating metal-organic framework (MOF) into a semiconducting amorphous MOF is described. Treatment of single crystals of copper(i) chloride trithiocyanurate, CuICl(ttcH3) (ttcH3 = trithiocyanuric acid), 1, in aqueous ammonia solution yields monoliths of amorphous CuI1.8(ttc)0.6(ttcH3)0.4, 3. The treatment changes the transparent orange crystals of 1 into shiny black monoliths of 3 with retention of morphology, and moreover increases the electrical conductivity from insulating to semiconducting (conductivity of 3 ranges from 4.2 × 10-11 S cm-1 at 20 °C to 7.6 × 10-9 S cm-1 at 140°C; activation energy = 0.59 eV; optical band gap = 0.6 eV). The structure and properties of the amorphous conductor are fully characterized by AC impedance spectroscopy, X-ray photoelectron spectroscopy, X-ray pair distribution function analysis, infrared spectroscopy, diffuse reflectance spectroscopy, electron spin resonance spectroscopy, elemental analysis, thermogravimetric analysis, and theoretical calculations.

Visualization inside polymer electrolyte fuel cells (PEFCs) for elucidating the reaction distributions is expected to improve the performance, durability, and stability. An oxygen-sensitive film of a luminescent porphyrin was used to visualize the oxygen partial pressures in five straight gas-flow channels of a running PEFC with liquid-water blockages formed at the end of the channels. The blockage greatly lowered and unstabilized the cell voltage. The oxygen partial pressure decreased nearly to 0 kPa in the blocked channel. With a water blockage in a channel, the oxygen partial pressures in the adjacent channels were lowered due to an extra demand of oxygen consumption. When the number of the blocked channels increased, the oxygen partial pressure in the unblocked channels became much lowered. When the water blockages disappeared, the oxygen partial pressures quickly returned to the values before plugging. The influence of the cross flows of air through the gas diffusion layers in straight channels was much smaller than that in serpentine flow channels. (C) 2014 Elsevier B.V. All rights reserved.

Redox-active, phenothiazine-functionalized polymers were synthesized and employed as a promising cathode-active material (similar to 3.7 V vs. Li, 77 Ah kg(-1)) in a rechargeable battery. The longer spacer between phenothiazine and the polymer backbone contributed to the stability of the formed radical cations, resulting in decelerated self-discharge and improved cycle performance.

Visualization of the oxygen partial pressures was carried out at the surface of a gas diffusion layer (GDL) for the first time together with the upper part of the gas-flow channel of the cathode of a running polymer electrolyte fuel cell (PEFC) using two different oxygen-sensitive luminescent dye films. The visualized distributions of the oxygen partial pressures at the GDL and the upper gas-flow channel during the PEFC operation were very different in a conventional test cell. The change in the distribution of the oxygen partial pressures was observed by changing the oxygen utilization, which should be connected with the reactive locations in the membrane-electrode assembly (MEA). A numerical calculation was carried out to understand the distributions of water and current density inside the MEA. The water distribution inside the MEA was confirmed to strongly affect the distributions of the current density and the oxygen /partial pressure. (C) 2014 Elsevier B.V. All rights reserved.

Ring-opening metathesis polymerization (ROMP) using Grubbs third-generation catalyst directly yielded a norbornene-based polymer bearing robust redox-active radicals without any protection. Successive addition of imidazolium-containing norbomene in a one-pot reaction during ROMP produced pendant radical- and ion-containing block copolymers. The diode-structured thin-film devices fabricated with the obtained block polymers that had morphologies of spheres, lamellae, and inverse spheres exhibited conductive switching (write-once read-many-times, WORM) under a bias voltage, which revealed the dominant effect of the location of radicals and ions in the microphase-segregated domains on memory characteristics.

The fabrication of modern microelectronic silicon devices mechanically challenges these thin silicon substrates during manufacturing operations. Melt and solution polyesterification enabled the synthesis of polyesters containing photoreactive o-nitro benzyl ester units for use as a potential photocleavable adhesive. Melt transesterification provided a solvent-free method for synthesis of 2-nitro-p-xylylene glycol (NXG)-containing polyesters of controlled molecular weights. 1H NMR spectroscopy confirmed the chemical composition of the photoactive polyesters. Size exclusion chromatography (SEC) determined the number-average molecular weights (Mn) of the polyesters synthesized in the range of 6000 to 12000g/mol. 1H NMR spectroscopy confirmed increasing levels of photocleavage of the o-nitro benzyl ester functionality with increasing exposure to broad wavelength UV irradiation, and exposure levels ranged from 0187J/cm2 UVA. Photocleaveage of approximately 90% of the o-nitro benzyl ester (ONB) units within the backbone of the polymer occurred at maximum dosage. Wedge fracture testing revealed approximately a two-fold decrease in fracture energy upon UV irradiation, suggesting that these structural adhesives offer potential for commercial flip bonding applications.

Redox-active but highly durable nitroxide radicals, that is, 2,2,6,6-tetramethylpiperidinyl-4-oxy (TEMPO), enabled direct electrospinning of radical-containing polymers without additional processing aids (such as polymer blends, post-doping, or protection/deprotection) and produced redox-active fibrous membranes with high surface area. The solution rheological behavior of the TEMPO-substituted polymethacrylate was similar to the neutral conventional polymers, and electrospinning of the radical polymers yielded submicrometer-scaled fibrous membranes without any defects on the radical moiety. The obtained membrane exhibited stable redox response, leading to redox catalysts or electrode-active materials toward organic-based flexible rechargeable battery. Polymer Journal (2012) 44, 264-268; doi:10.1038/pj.2011.120; published online 7 December 2011

"Radical polymers" bearing a high density of unpaired electrons in a pendant, non-conjugated fashion on each repeating unit were utilized as cathode- and anode-active materials in a totally organic-based rechargeable battery. Careful molecular design of radical polymers such as nitroxide and galvinoxyl derivatives produced remarkably stable p- and n-type redox couples, which provided three different battery configurations. The power-rate performance of these cells was excellent (360 C rate, 10 sec charge/discharge), as a result of the rapid redox process of the organic radical moieties in the amorphous polymer layer. Organic polymer-based electrodes also allowed their utilization to a flexible, paper-like, and transparent rechargeable energy-storage device. © 2012 American Chemical Society.

Start-up and shut-down cycling in PECFs causes severe degradation, because the carbon supports at the cathode catalyst layers are corroded due to the instantaneous reaction with H2O. We developed a new CO2 visualization system using a CO2-sensitive dye for detecting the generation of CO2 during the corrosion processes in real time and with spatial resolution. The corrosion occurring during the shut-down process continued longer near the inlet and produced a more serious effect than during the start-up process, near the outlet. This new CO2 visualization technique should help to minimize the corrosion of carbon supports in all types of PEFCs. (C) 2012 The Electrochemical Society. [DOI:10.1149/2.018204esl] All rights reserved.

A TEMPO-substituted ionic liquid was selectively incorporated into well-defined, self-assembled block copolymer templates, which served as an active layer for organic nonvolatile memory. Phase structures (sphere, cylinder, and lamellae) and their orientation modulated the resistive switching behavior, which demonstrated the unprecedented, morphology-driven charge transport in the organic electronic devices.

Radical polymers bearing a high density of unpaired electrons in a pendant, non-conjugated fashion on each repeating unit provided a rapid, reversible, and quantitative redox behavior in an electrode form. Careful selection of radicals (TEMPO, galvinoxyl, and nitronylnitroxide, etc.) produced remarkably stable p- and n-type redox couples, which lead to the totally organic-based rechargeable batteries. The power-rate performance of these cells was excellent (360 C rate, 10 sec charge/discharge), as a result of the simple, rapid redox process of the organic radical moieties with no associated structural change in the amorphous polymer layer. Organic polymer-based electrodes are amenable to roll-to-roll or inkjet processing, which allowed the fabrication of a flexible, paper-like, and transparent rechargeable energy-storage device, which could be embedded in radio-frequency identification tags, smart cards and electronic paper.

The p- and n-type bipolar redox-active radical polymer with a nitronylnitroxyl group, poly(nitronylnitroxylstyrene), expands its utilization as a cathode-or anode-active material in organic polymer-based rechargeable devices with two unprecedented configurations: a poleless battery and a "rocking-chair type" battery. These batteries exhibit a remarkably high power rate capability (chargeable within 20 s) and high cycle performance.[GRAPHICS].

To maximize the theoretical redox capacity of polymers containing cyclic nitroxides as redox active pendant groups for high density charge storage application, a compact five membered ring with the smallest equivalent weight among the robust cyclic nitroxides was directly bound to a poly(ethylene oxide) chain 2,2,5,5 Tetramethyl 3 oxiranyl-3-pyrrolin 1 oxyl was synthesized and polymerized via anionic coordinated ring-opening polymerization utilizing diethyl zinc/H2O as an initiator The unpaired electron in the monomer survived during the polymerization giving rise to a high density redox polymer with a weight-specific theoretical capacity of 147 mA h/g Cyclic voltammetry of the polymer layer confined at the surface of an electrode revealed a large redox capacity comparable to the theoretical capacity which was ascribed to the efficient swelling and yet insoluble properties of the polyether in electrolyte solutions by virtue of the high molecular weight of >10(5) and adhesive properties allowing immobilization of the layer on the electrode surface The redox capacity also indicated that the ionophoric polyether matrix accommodated electrolyte anions through the polymer/electrolyte interface to neutralize positive charges produced by the oxidation of the neutral radicals at the polymer/electrode interface The diffusion coefficient for the redox gradient driven charge hopping process corresponded to a large second order rate constant in the order of 10(7) M-1 s(-1), which suggested an efficient electron self-exchange reaction throughout the polymer layer due to the large redox site population and hence to the small intersite distance Test cells fabricated with a polymer/carbon fiber composite layer on an aluminum current collector as the cathode and a Li anode sandwiching an electrolyte layer were capable of charging and discharging as a secondary battery with an output voltage near 3 7 V and were durable for more than 10(3) charging discharging cycles without substantial degradation

Polyimides and poly(siloxane imide)s containing photo-active cyclobutane diimide units were developed as reversible adhesives for temporary bonding in micro-fabrication processes. Poly(amic acid) formation in dipolar aprotic solvents and subsequent chemical or thermal solution imidization yielded the corresponding organic soluble polyimides. Incorporation of nonplanar (alicyclic or bicyclic) structures and poly(dimethyl siloxane) blocks into the main chain improved the solubility. The synthesized poly(siloxane imide)s afforded tough and ductile films, which exhibited a rubbery plateau in the storage modulus, as observed using dynamic mechanical analysis. This plateau was attributed to the microphase-separation of the poly(dimethyl siloxane) segments and the polyimide segments. Spin-coated thin films on silicon substrates were photo-degraded with ultraviolet-C (UVC) light (254nm). Nuclear magnetic resonance (NMR) spectroscopy demonstrated a growth in the proton resonance corresponding to the formation of maleimide functionality upon photo-cleavage. This observed photo-cleavage suggests possible applications as temporary structural adhesives.

Two redox-active poly(oxoammonium salt)s were synthesized via chemical oxidation of a TEMPO-substituted polymer, or conventional radical polymerization of the oxoammonium monomer, respectively. The diode-structured thin film device composed of poly(oxoammonium salt) with radical conc. of 6-43% exhibited a resistive switching behavior (ON-OFF ratio > 10(3)), in contrast to the radical-free poly(oxoammonium salt), which revealed that the coexistence of radical/oxoammonium salts contributed to a significant change in I-V characteristics.

A n-type and redox-active radical polymer bearing galvinoxyl radicals, poly (galvinoxylstyrene), is utilized as an anode-active material, which enabled, for the first time, the fabrication of a totally organic polymer-based rechargeable battery in conjunction with p-type redox-active radical polymer. This battery was characterized by its remarkably high power rate capability.

A series of poly(arylene ether sulfone) copolymers containing the diazocine unit (0, 20, 50, 80, 100 mol %) were synthesized via step-growth polymerization. Copolymer compositions exhibited number-average molecular weights exceeding 30 000 g/mol, and mechanically ductile films were obtained for all compositions. The random copolymers exhibited enhanced thermal stability (T-d10% = 500-550 degrees C) and mechanical properties (tensile stress = 45-65 MPa), and the thermomechanical performance was predictable based on copolymer composition. A secondary transition in the dynamic mechanical analysis appeared at 28 degrees C, which was attributed to segmental motion of the bulky diazocine and biphenyl units. X-ray single crystallography and H-1 NMR spectroscopy as a function of temperature revealed that the diazocine ring existed in the boat-shaped conformation. The effective dipolar couplings of site-specific H-1-C-13 dipolar couplings in the aromatic rings were measured using DIPSHIFT solid state NMR spectroscopy at various temperatures. The experimental data indicated that the bulkier diazocine group experienced slower ring-flip motion than the smaller phenylene group. Cyclic voltammograms of diazocine-containing poly(arylene ether sulfone)s exhibited two reversible reduction peaks at -0.68 and -1.21 V under inert and basic conditions. UV spectra of the diazocine group in the reduced state indicated an extended pi-electron structure, which supported the boat- to planar-conformational change (molecular actuation) via redox reactions.

Reversible adhesion has long been of significant practical interest for a range of applications including controllable adhesion, photolithography, temporary bonding required for wound dressings and certain manufacturing processes, and disassembly for repairing and recycling. UV degradable materials find applications in medical and microelectronic fields due to their dramatic property changes after UV irradiation, allow for easy removal of the adhesive. A series of UV cleavable adhesives has been synthesized to investigate their ability to debond more readily as a function of UV radiation dosage. In this paper a wedge test, from elevated temperature exposure or photo-degradation, is used to measure the reduction in resistance to debonding. By using fracture mechanics principles and recording the growing debond length as a function of exposure, the fracture energy can be determined. Tests are conducted to measure how fracture energy decreases after varying amounts of thermal exposure or UV irradiation. The debond surfaces and locus of failure are also investigated in this study.

Robust but redox-active radical polymers bearing 2,2,6,6-tetramethylpiperidin-N-oxy (TEMPO) were investigated as a metal-free, green mediator/catalyst for the oxidation of alcohol derivatives, and as a new electrode-active and charge-storage material. The TEMPO-mediated oxidation of the primary alcohol group of the natural cellulose improved the water-dispersivity of cellulose, and the polymer-supported catalysts or redox resins allow facile removal of catalysts from products by simple filtration. Other radical molecule (e.g. galvinoxyl) was also used as a mediator, which is coupled with the molecular oxygen. A reversible one-electron redox reaction of TEMPO allowed its application as an electrode-active material featuring high cyclability (> 500 cycles), relatively high battery electrode capacity (100-135 mAh/g), and fast electrode kinetics, leading to the high power rate capability of the battery. The radical polymer-based electrodes also provided good processability and shape flexibility, which promised the paper-like and wearable energy-storage devices.

In search of polymer backbones to bind organic radical pendant groups as redox centers for high-density charge storage application, polyether was employed as a flexible chain with a low glass transition temperature and affinity to electrolyte solutions. Cyclic ethers bearing nitroxide radicals were synthesized and polymerized via ring-opening polymerization utilizing various initiators. Polyethers bearing robust radical substituents such as 2,2,6,6-tetramethylpiperidin-l-oxyl-4-yl and 2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-l-oxyl-3-yl groups with high density, i.e., per repeating unit with small equivalent weights, were prepared by the anionic polymerization of the corresponding epoxides. Cyclic voltammetry of the radical polyethers, obtained for polymer/carbon composites confined at an aluminum current collector, revealed large redox capacities comparable to the formula weight-based theoretical values, which was ascribed to the efficient swelling and yet insoluble properties of the polyethers in electrolyte solutions by virtue of their high molecular weights and adhesive properties to be held on electrode surfaces. The redox capacity also indicated that the ionophoric polyether matrix accommodated electrolyte anions to compensate positive charges produced by the oxidation of the neutral radicals at the polymer/electrode interface, allowing charge propagation deep into the polymer layer by a site-hopping mechanism. Test cells fabricated with the polymer/carbon composite as the cathode and a Li anode, sandwiching an electrolyte layer, performed as a secondary battery at output voltages near 3.6 V without substantial degradation even after 100 charging-discharging cycles.

Three polystyrenes bearing redox-active nitroxide radical(s) in each repeating unit, poly[4-(N-tert-butyl-N-oxylamino)styrene] (1), poly[3,5-di(N-tert-butyl-N-oxylamino)styrene] (2), and poly[4-(N-tert-butyl-N-oxylamino)-3-trifluoromethylstyrene] (3), were synthesized via free radical polymerization of protected precursor styrenic derivatives and subsequent chemical oxidation. The radicals in these polymers were robust at ambient conditions, and the polymers possessed radical densities of 2.97 x 10(21), 4.27 x 10(21), and 1.82 x 10(21) unpaired electrons/g for 1-3, respectively, resulting in an electrode-active material with a high charge/discharge capacity. Particularly, the dinitroxide functional polymer 2 possessed the highest radical density. Cyclic voltammetry of the poly(nitroxylstyrene) 1 revealed a reversible redox at 0.74 V vs Ag/AgCl, which was assigned to the oxidation of the nitroxide radical to form the oxoammonium cation (p-type doped state). On the other hand, the poly(nitroxylstyrene) ortho-substituted with the electron-withdrawing trifluoromethyl group 3 showed a reversible redox at -0.76 V, ascribed to the n-type redox pair between the nitroxide radical and the aminoxy anion. Thus, the nitroxide radical polymer could be switched from p-type material suitable for a cathode to n-type material (anode-active) via altering the electron-withdrawing character of the substituents on the poly(nitroxylstyrene). This is the first report of an n-type radical polymer and the first report of using substituent effects to switch the redox behavior of the polymer. This versatile switching ability enables these polymers to function as components of metal-free electrodes in rechargeable batteries.

A nitroxide radical functional polymer was photocrosslinked for the first time without significant side reactions, producing a cathode-active thin film, leading to an organic-based paper battery.

A nitroxide radical is electrochemically oxidized to the oxoammonium cation(p-type doping) and reduced to the nitroxide reversively. Based on this redox property, we have reported application of the nitroxide radical polymer to an electrode-active material. Epoxide derivatives bearing 2,2,6,6- tetramethylpipelidine-A/-oxyl were synthesized and polymerized by ring-opening polymerization. In this report, the obtained polymers were characterized by IR, elemental analysis, ESR and SQUID measurement. Redox property of these radical polymers was examined by cyclic voltammetry. The cycle performance during charging and discharging of the fabricated cell displayed a plateau voltage at 3.7 V, and no significant deterioration in the capacity was observed more than 100 cycles.

Galvinoxyl radical, known as a stable organic radical, was selected as a new candidate for a cathodeand/or anode-active material for a secondary battery. Styrene derivative bearing the galvinoxyl radical was synthesized via four steps, and polymerized to give the precursor polymer (Mn=10 4). Chemical oxidation yielded the corresponding radical polymer. The obtained polymer was characterized by spectroscopic measurements. Electrochemical measurements revealed its stable redox behavior. The cell performance will also be reported.

Based on the redox couples of a nitroxide radical, organic radical polymers have been utilized as the electrode-active or charge-storage component for a secondary battery, so-called "organic radical battery". Organic radical battery has several advantages: high capacity, high power-rate performance, long cycle ability, and environmentally-benign features. We report here the synthesis of a series of radical polymers and their redox properties. TEMPO-substituted polyether displayed its improved compatibility with the electrolyte solution. Photo-crosslinking of TEMPO-substituted polynorbornene was investigated as a facile and useful method leading to a slim and flexible battery. Poly (galvinoxystyrene) displayed a stable n-type redox behavior at 3.2 V vs. Li/Li+, which also holds considerable potential as an anode-active material, leading to purely organic-derived batteries. The cell performance will be also reported.

Diphenylnitroxide derivatives are known to their high radical stability and stable redox properties suitable as an electrode-active material of the next generation secondary battery. A series of p, p'-disubstituted diphenylnitroxide derivatives were synthesized, and p-substituent effect on their redox properties were investigated by electrochemical measurements. Styrene derivative bearing the diphenylnitroxide radical was synthesized via 4 steps, and polymerized to give the precursor polymer (Mn =3.2 × 103). Chemical oxidation of this polymer yielded the corresponding radical polymer. Its redox behavior will be also reported.

Poly(TEMPO-substituted norbornene) was synthesized by ring-opening metathesis polymerization by using Grubbs catalyst. The polymer was photo-crosslinked by bisazide or oxetane derivatives, and applied to an electrode-active material. The obtained radical thin film displayed a stable redox behavior at 3.6V vs. Li/Li+.The test cell was fabricated with the polymer cathode and lithium anode.No deterioration of the capacity was observed after 500 cycles.

Nitroxide-substituted polyether was synthesized as a cathode-active material for a secondary battery. Anionic ring-opening polymerization of a TEMPO-bearing glycidyl ether was carried out under bulk conditions to yield the corresponding polymer with the molecular weight of >104. The obtained polymer was insoluble, but slightly swollen in the electrolyte solution (ethylene carbonate/propylene carbonate). The test cell fabricated with a carbon composite cathode of this radical polymer displayed a plateau voltage at 3.5 V vs. Li/Li+. The cell performance was maintained even with a higher amount of the radical polymer loaded in the composite electrode, which could be ascribed to the flexible and rubbery polyether backbone and its higher compatibility with the electrolyte solution. Copyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.

The charging and discharging mechanism of a prototype organic radical-based lithium-ion battery, where the p-type nitroxide radical polymer forms a cathode operated in conjunction with a carbon anode, are discussed. During the charging process, the p-type radical polymer in the cathode is oxidized to the oxoammonium form. During the discharging process, the nitroxide radical is regenerated by reduction of the oxoammonium. The organic radical polymer has solvent solubility and processability, which facilitates battery manufacture through a wet, printable, and rollable process.

A nitroxide radical is able to be electrochemically oxidized to the corresponding oxoammonium cation (p-type doping) and reduced to the aminoxyl anion (n-type doping). These redox properties are suitable as an electrode-active material of a next generation secondary battery. We have reported an application of TEMPO-substituted polymethacrylate to an cathode material. We report here synthesis of two nitroxide-substituted polystyrene derivatives and their electrochemical properties. Cyclic voltammogramsoftheradicalpolymersshowedthep- or n-type reversible waves which are tunable by molecular designing. TEMPO-substituted polynorbomene was synthesized by ring-opening metathesis polymerization. The solubility and processability of the radical polymer was tuned by cross-linking. The electron transfer process in the polymer composite electrode was examined by CV, normal pulse voltammmetry, and impedance measurement. The cell performance was also investigated.

Nitroxide radical electrochemically can be oxidized to oxoammonium cation(p-type doping) and reduced reversively. Based on these redox properties, we have reported the application of nitroxide radical to an electrode-active material. In this report, we synthesized polyethyleneoxide derivatives bearing 2,2,5,5-tetramethylpirrolidine-N-oxyl(proxyl radical) and studied their redox properties. 2,2,5-trimethyl-5-oxiranylmethylpyrrolidin-1-yloxy was synthesized from 2-nitropropane via four step reactions. The obtained proxyl-substituted epoxide was polymerized by ring-opening polymerization. Poly(proxyl radical)s were identified by IR, ESR, SQUID measurement, and elemental analysis. Redox properties of these polyradicals were examined by cyclic voltammetry. The formal potential was 0.75V.

A nitroxide radical is stable at ambient conditions and has two redox couples; nitroxide radical is oxidized to oxoammonium cation (p-type doping) and reduced to aminoxyl anion (n-type doping). Based on these electrochemical properties, the nitroxide radical is expected as an electrode active material of secondary battery. In this report, we synthesized new polyacetylene derivatives bearing 2,2,5,5-tetramethylpyrrolidine-N-oxyl(proxyl radical) and studied their electrochemical properties. Two monomers were synthesized by Grignard reaction (from nitrone). The obtained acetylene monomer was polymerized by coordination polymerization and oxidized to its radical derivative. Poly(proxyl radical)s were identified by IR, ESR, SQUID measurement, and elemental analysis. Redox property of these poly(proxyl radical)s was examined by cyclic voltammetry.

The nitroxide radical is expected as an electrode active material of secondary battery. We synthesized polystyrene derivatives bearing nitroxide radical and investigated their electrochemical properties. Styrene monomer was synthesized from 5-bromo-2-aminobenzotrifluoride via four step reactions. The obtained styrene monomer was polymerized by radical polymerization and oxidized to its radical derivative. Electrochemical property of the radical polymer was examined by cyclic voltammetry. The formal potential was -0.76 V.

Purely organic-derived nitroxide radicals, including their polymer derivative, poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PTMA), were characterized as a new class of cathode-active materials for lithium batteries. PTMA was stable at ambient conditions, had a tunable solubility and processability, and could undergo thermal runaway without any odor and ash. The nitroxide radicals displayed a reversible and very rapid redox to form their oxoammonium salts, which enabled a high power-rate performance during the charge and discharge process of the battery. © 2004 Elsevier Ltd. All rights reserved.

The electron-transfer rate constants of nitroxide derivatives, 4-(N-t-butyl-N-oxylamino)-t-butylbenzene, 4-(N-t-butyl-N-oxylamino) methoxybenzene, and 2,2,6,6-tetramethylpiperidinyl-N-oxyl, were investigated by electrochemical methods, which demonstrated that these radicals can potentially be used as a high power-rate electrode-active material due to their fast electron-transfer process.