Molecular Engineering of Perylene Imides for High-Performance Lithium Batteries: Diels-Alder Extension and Chiral Dimerization.

The search for high-performance electrode materials in organic rechargeable batteries remains a key challenge. Reported herein is a molecular structural modification of perylene imides, a promising class of redox-active electrode materials, for improved battery performance. The Diels-Alder extension of perylene imides at the lateral position led to the simultaneous incorporation of two electron-withdrawing carbonyl groups and extension of the π system, which is supposed to favor high specific capacity, operating voltage, and electronic conductivity. After the chiral dimerization of the extended species with 1,2-diaminocyclohexane, it was anticipated that the porosity and coulombic interactions with lithium ions would be promoted, which would be beneficial for fast reaction kinetics and long cycling life. As expected, in lithium batteries, the obtained chiral and π-extended tweezer, which features six imide groups and a porous solid-state network of 42.2 % accessible cell volume, was found to deliver a reversible capacity of 92.1 mA h g at a charge/discharge rate of 1 C within an operating voltage window of 1.60-2.80 V versus Li /Li, around 75 and 50 % of which was maintained after 100 and 300 galvanostatic cycles, respectively, much better than those of unmodified species.