Stable Poly(3,4-Dioxythiophene) Radical With Superior Electron and Ion Conductivity as High-Performance Anode for...

Organic radical batteries (ORBs) with small molecule and polymer radicals as electrode materials for lithium-ion batteries have attracted world-wide research interest owing to the advantages of the high structural diversity, low cost, and superior sustainability. Herein, in contrast with the traditional doped 3,4-ethylenedioxythiophene (PEDOT), a new stable non-doped organic radical polymer poly(3,4-ethylenedioxythiophene)-3,4-dioxothiophene (PEDOT-TO₂) with enhanced spin concentration was readily prepared for the first time via one-step simple reaction. Attributed to the highly reversible interaction between PEDOT-TO₂ radicals and lithium ion as well as impressive electronic/ionic conductivity, the PEDOT-TO₂ can deliver outstanding initial specific capacity of 340 mAh g^-1 under the current density of 0.1 A g^-1, high capacity retention rate (100% after 3500 cycles at 2.0 A g^-1), and high rate capability (159.6 mAh g^-1 at 10.0 A g^-1) when evaluated as an anode for Li-ion battery, which is superior to most previously reported organic radical anodes. Besides, the LiFePO₄//PEDOT-TO₂ full cell can show impressive rate performances and cycle stability. The extremely high air stability and superior electrochemical stability contribute to the great potential of PEDOT-TO₂ as anode material in energy storage, which enriches the library of potential organic electrochemical active electrodes, including cathodes and solid-state electrolytes.