A polythiophene derivative bearing TEMPO as a cathode material for rechargeable batteries

A polythiophene derivative bearing TEMPO radical was synthesized by oxidative chemical polymerization of its monomer. The polymer had a high spin density (2.05 × 1021 spins/g of polymer). CV studies of the polymer showed that the electrochemical redox reaction of the TEMPO radicals were completely reversible. We demonstrated, for the first time, construction and charge/discharge characteristics of an organic radical battery utilizing a TEMPO bearing polythiophene based cathode material. The battery had an initial specific discharge capacity of 79 A h/kg (87% of the theoretical capacity) and an average output voltage of 3.6 V. The specific energy capacity initially discharged was 268 W h/kg.

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► A polythiophene derivative carrying TEMPO radicals with a high spin concentration is synthesized.
► A composite cathode material is prepared by mixing this polymer with graphite as a conductivity aid.
► A battery is assembled by using this composite cathode and a lithium metal anode.
► This battery had initial specific charge and energy capacities of 79 A h/kg and 268 W h/kg, respectively.