Grafting of a redox polymer onto carbon nanotubes for high capacity battery materials

In this contribution we disclose an original strategy towards dense grafting of electrochemically active nitroxide-bearing polymer brushes on multi-walled carbon nanotubes (MWCNTs). Our strategy involves the surface initiated polymerization of 2,2,6,6-tetramethylpiperidin-4-yl methacrylate (TMPM) through atom transfer radical polymerization from the high-density initiator functionalized surface of MWCNTs and the oxidation of accordingly obtained PTMPM into poly(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) (PTMA), leading to MWCNT-g-PTMA composites. Extended chemical and morphological analysis confirmed the compact core-shell morphology with a high active material mass loading of 60 wt%. The electrodes made out of these MWCNT-g-PTMA composites display good cycling stability (87% of capacity retention after 200 cycles), good rate capabilities and an excellent specific capacity (85% of the theoretical capacity). The success of this strategy offers new opportunities to overcome the issue of PTMA solubilization through an electrolyte and minimal utilization of conductive carbon species.