An Aluminum-Benzo[1,2-b:4,5-b ']dithiophene-4,8-dione Organic Rechargeable Battery Featuring Low Self-Discharge

The achievable cell-level specific energy density of existing aluminum-ion batteries (AIBs) employing AlCl4- intercalation type cathodes is intrinsically limited by the chloroaluminate anolyte. Towards achieving AIBs with higher specific energy, it is imperative to explore alternative cell chemistries that fundamentally tap the capacity of Al metal anode. Here, we report a benzo[1,2-b:4,5-b']dithiophene-4,8-dione (BDTD) organic electrode material with favorable AlCl2+ intercalation mechanism. This BDTD cathode delivers a specific capacity of 143 mAh g(-1), and the resulting battery exhibits a well-defined voltage plateau at similar to 1.2 V. This characteristic voltage plateau is mainly driven by the predominant diffusive charge storage in BDTD cathode, which accounts for up to 85 % of the total charge-storage contribution. As a result, the BDTD cathode demonstrates exceptional self-discharging resistance by recovering >95 % of its capacity upon 24-h resting.