Poly(3-Methylthiophene)/Graphene Composite Cathode for Rechargeable Aluminum-Ion Batteries.

To reduce the dependence on traditional fossil energy, developing efficient energy storage systems is urgent. The reserves of aluminum resources in the earth's crust are extremely rich, which makes aluminum-ion batteries a promising competitor of new energy storage devices. Here, we report a poly(3-methylthiophene)/graphene (P3TH/Graphene) composite as the cathode of an aluminum-ion battery. The adjustment of polymer chain spacing by the methyl side chain provides a channel conducive to the transport of large-size AlCl4- complexes. The addition of electron donor groups also changes the electron delocalization characteristics of polymers and improves the specific capacity of the material. At the same time, the in situ composite of graphene can enhance the Π-Π interaction to form a favorable electronic transmission channel. At a current density of 200 mA g-1, the P3TH/Graphene composite showed a specific capacity of ∼150 mA g-1. The flexible structure of the polymer also guarantees the excellent rate capability of the composite.