Synthesis and properties of novel TEMPO-contained polypyrrole derivatives as the cathode material of organic radical battery

摘要: Abstract Two 2,2,6,6-tetramethylpiperidinyl-N-oxy (TEMPO) contained polypyrrole (PPy) derivatives with the different side-chain length were synthesized by esterification of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radial pyrrole butyric acid and caproic acid. Then homopolymers 4-(3-(Pyrrol-1-yl)butyryloxy)-2,2,6,6-tetramethylpiperidin-1-yloxy (PPy-B-TEMPO) 4-(3-(Pyrrol-1-yl)hexanoyloxy)-2,2,6,6-tetramethylpiperidin-1-yloxy (PPy-C-TEMPO) prepared chemical oxidative polymerization. The structure, morphology, electrochemical properties polymers characterized fourier transform infrared spectroscopy (FTIR), ultraviolet visible (UV-vis), scanning electron microscopy (SEM), cyclic voltammograms (CV) impedance spectra (EIS), respectively. Also, charge-discharge studied galvanostatic testing. results demonstrated that as-synthesized nitroxide radical showed a reversible two-electron redox reaction process in potential limits 2.5–3.0 V 3.4–3.8 V vs Li/Li+, Under our experimental conditions, PPy only presented discharge capacity 16.5 mAh·g−1 at 20 mA·g−1 between 2.5 4.2 V, while PPy-B-TEMPO short linked to TEMPO groups exhibited an initial up 86.5 two well-defined plateaus. Furthermore, PPy-C-TEMPO longer linking even displayed 115 mAh·g−1. These superior performances ascribed flexible introduction stable conductive main chain, which benefits improvement charge carrier transportation aggregated polymer bulk.