Synthesis, Characterization, and Charge/Discharge Properties of Polynorbornenes Carrying 2,2,6,6-Tetramethylpiperidine-1-oxy Radicals at High Density

Abstract

TEMPO-containing norbornene monomers 1-8 (TEMPO ) 2,2,6,6-tetramethylpiperidine-1-oxy) were synthesized and polymerized via ring-opening metathesis using a ruthenium-carbene catalyst. The TEMPO moiety did not inhibit the polymerization, and the monomers gave corresponding polymers in good to high yields. Poly(2) and poly(3) were soluble in common solvents and possessed high molecular weight, while other polymers were insoluble. The resulting polymers were thermally stable up to ca. 240 °C according to TGA measurements in air. In the case of poly(1)-poly(3), the charge/discharge capacities of the polymer-based cells were largely dependent on the spatial arrangement of the two TEMPO moieties on each repeating unit. Quite interestingly, the capacity of the poly(2)-based cell reached its theoretical value (109 A h/kg), and a large capacity (>90 A h/kg) was retained even at high current densities up to 6 A/g, indicating the possibility of very fast charging (within 1 min). The cells utilizing the present polymers as cathode-active materials demonstrated excellent cycle life; e.g., the discharge capacities of poly(2) and poly(3) showed no more than 10% decrement even after 400 cycles.

Organic Electrode Materials for Rechargeable Lithium Batteries

“…[ 125,126 ] In particular, nitroxide 75 discharges ∼ 90% of the C theo at a current density of ∼ 70C. [ 127 ] By comparison of the electrode performance of polynorbornenes 79 and 80 , Masuda et al revealed an interesting spatial effect that although the distance between the two TEMPO fragment for the endo , endo -isomer 80 is smaller than that for the endo , exo -isomer 79 , the utilization of the former ( ∼ 50%) is inferior to the latter ( ∼ 100%). [ 127 ] By comparison of the electrode performance of polynorbornenes 79 and 80 , Masuda et al revealed an interesting spatial effect that although the distance between the two TEMPO fragment for the endo , endo -isomer 80 is smaller than that for the endo , exo -isomer 79 , the utilization of the former ( ∼ 50%) is inferior to the latter ( ∼ 100%).…”

A Methoxyamine‐Protecting Group for Organic Radical Battery Materials—An Alternative Approach

“…Polymers with pendant nitroxide moieties have previously been synthesized by various polymerization techniques, including ring‐opening metathesis polymerization (ROMP), ring‐opening polymerization, anionic, group transfer, and radical polymerization . While radical polymerization is generally the most widely employed polymerization technique, owing to its ease of use and straight forward reaction conditions, nitroxide‐bearing monomers cannot be directly polymerized because of the nitroxide's radical scavenging nature and inhibition effect on free radical chain propagation.…”

Poly(exTTF): A Novel Redox‐Active Polymer as Active Material for Li‐Organic Batteries

“…The second generation of organic batteries eluded this problem by utilization of polymers with pendant nonconjugated redox‐active groups. In particular organic radicals such as nitroxides, galvinoxyls, nitronylnitroxides, and arylnitroxides have been studied intensively, but also other redox‐active compounds such as triarylamines, carbazoles, or ferrocene were utilized. Most of these compounds possess an ordinary one‐electron redox reaction, leading to a single charge/discharge plateau with a constant cell potential.…”