Triphenylamine‐Supported Benzoquinone Polymer as High Performance Cathode for Lithium‐Ion Batteries

Abstract Benzoquinone (BQ) electrode is regarded as next generation energy storage material for lithium ion batteries (LIBs) because of its advantages of high theoretical specific capacity, abundant source, environmental friendliness. However, the two key challenges, the dissolution of BQ in organic electrolyte and the low discharge plateaus, impede practical application of BQ as cathode. Here, triphenylamine (TPA) with high working voltage and BQ with high theoretical capacity are used to synthesize triphenylamine‐benzoquinone monomer (TPA‐BQ) and its polymer (poly triphenylamine‐benzoquinone (PTPA‐BQ)) as cathodes for LIBs. The charge/discharge results reveal that the discharge plateaus of TPA‐BQ and PTPA‐BQ increase from ~2.5 V to ~3.5 V, and PTPA‐BQ exhibits high discharge capacity and remarkable cyclic stability compared with TPA‐BQ. The electrochemical mechanism shows that the redox peak potential of ~2.3 V/~2.2 V are assigned to the insertion/extraction of lithium ion in C=O groups of BQ, while at high potential of ~3.6 V/~3.5 V corresponds to the de‐dope/dope of the PF 6 − anion in TPA unit. The results demonstrate TPA was introduced BQ into small molecule to form PTPA‐BQ polymer that can improve discharge plateaus and charge/discharge performance of BQ small molecule, which provide guides for solving the dissolution and discharge platforms of the other organic electrode materials.