Synthesis of poly(TEMPO-substituted glycidyl ether) by utilizing t-BuOK/18-crown-6 for an organic cathode-active material

A nitroxide radical-substituted polyether, poly(TEMPO-substituted glycidyl ether) (PTGE), was synthesized using a potassium tert-butoxide/18-crown-6 initiator. The presence of 18-crown-6 effected significant improvement in the reactivity of the chain end, thus allowing the polymerization to proceed at moderate temperatures to suppress the deactivation of the pendant nitroxide group. A high molecular-weight polyether with a theoretical radical concentration was first obtained in high yield. Charging and discharging cyclability was much improved by cross-linking, which helped the electrode-active material stay on a current collector during the electrolysis. The polymer/vapor-grown carbon nanofiber composite electrode exhibited a redox capacity comparable to the formula weight-based theoretical density over 10³ cycles and fast charging/discharging capability up to a rate of 60 C which corresponded to full charging and discharging in 60 s. The redox capacity was almost maintained for a composite layer with a remarkably high polymer ratio of 90 %, which demonstrated the presence of effective percolation network of the carbon nanofiber due likely to the affinity of the polyether to the carbon material.