Conductive nonconjugated radical polymer as high capacity organic cathode material for high-energy Li/Na ion batteries

A nonconjugated radical polymer poly (4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) (PTEO) is explored as organic cathode material in Li and Na ion batteries for the first time. The PTEO exhibits a high electrical conductivity of 0.13 S m −1, far exceeding other organic cathode materials ranging from 10 to 10 to 10-5 S m −1. It offers high redox potentials with platueas at ~3.6 V vs. Li +/Li and 3.3 V vs. Na +/Na, respectively. The PTEO cathode with only 30 wt% carbon additive agent delivers a capacity of over 200 mAh g-1 and energy density of more than 500 Wh kg-1 for both Li/Na ion batteries. Reaction mechanism of the PTEO proceeds through the neutral state nitroxide radical (N–O·) to oxoammonium cation (+NO) and the aminoxy anion (N–O -). The PTEO is the only radical polymer that can deliver a capacity over 200 mAh g −1 for organic cathodes with no more than 50% carbon additive agent, making it a promising organic cathode material for Li/Na ion batteries.