Multiple Redox Site π-Conjugated Materials for Aqueous Aluminum-Organic Battery Cathodes

In the field of rechargeable aqueous aluminum batteries (AABs), carbonyl- and imine-based organic materials have received much attention due to their design flexibility. However, such materials usually face problems such as low capacity and poor stability. For this reason, a simple dehydration condensation method was employed to design a redox-active organic material (ROM)-BQPT (benzo[i]benzo[6,7]quinoxalino[2,3,9,10]phenanthrol[4,5-abc]phenazine-5,10,16,21-tetraone) of pi-conjugated structure enriched with multiple C=O and C=N groups. Due to the introduction of more redox-active sites, BQPT can provide an extremely striking capacity of 396.4 mAh g(-1 )at 0.2 A g(-1). Additionally, the abundant pi-pi structural interactions endowed BQPT with good structural stability and low solubility. In addition, further theoretical calculations confirm that the reorganization of the electron cloud and the expansion of the pi-conjugated ligand improve the redox kinetics of BQPT. Combined with ex situ characterizations, its reaction mechanism with Al(OTF)(2)(+) was elucidated. This study provides a significant reference for the design of new types of ROMs.