Elucidating the Extraordinary Rate and Cycling Performance of Phenanthrenequinone in Aluminum-Complex-Ion Batteries

Aluminum batteries are of great interest in “beyond-lithium” battery research because of their remarkably high performance in terms of rate capability and cycle life, in addition to the intrinsic advantages of aluminum metal such as its natural abundance and high theoretical capacity of 8056 mAh cm –3 . The electrochemical performance that has been achieved thus far is unusual, as cells usually adopted viscous ionic liquid (IL) electrolytes with bulky complex carrier ions. Herein, we not only demonstrate the excellent rate and cycling performance of phenanthrenequinone (PQ) but also elucidate the origin of this extraordinary performance. Density functional theory (DFT) calculations and experimental analyses jointly revealed that the long-term cyclability of PQ arises from PQ–AlCl 2 complexation, which lessens the effective charge of PQ to mitigate its dissolution into the electrolyte. Mo…