A PROXYL‐Type Norbornene Polymer for High‐Voltage Cathodes in Lithium Batteries

A newly designed radical polymer with a polynorbornene backbone and unsaturated derivative of tetramethylpyrrolidine 1-oxyl (PROXYL) as pendant groups displays reversible redox at 3.75 V (vs Li/Li⁺ ). The robust polymer design enables the high voltage while maintaining a promising cyclability (over 1000 cycles). The polymer is also beneficial as an additive to the regular lithium iron phosphate electrodes, where the quickly responding organic material facilitates the charging reactions catalytically.