Tuning Electrochemical Properties of Nitroaromatic Cathodes by Function‐Oriented Design for Rechargeable Lithium‐Ion Batteries

Abstract

Rechargeable lithium-ion batteries (LIBs) based on organic cathodes are an attractive alternative energy storage technology owing to the low cost and sustainability. Recently, nitro functionality in dinitrobenzenes is successfully demonstrated as an electrochemically reversible high-capacity redox group. In this study, a function-oriented design is employed to further disclose the effects of substituting functional groups and molecular conjugate structures on electrochemical properties of a range of nitroaromatic derivatives as organic cathodes for rechargeable LIBs. In specific, it is revealed that the redox potential of nitroaromatic cathodes can be effectively adjusted by introducing distinct electronically inducible functional groups, while the cyclic life can be significantly prolonged with the introduction of the hydrophilic groups. When constructed with extended π-conjugated structures, the electronic conductivity and electrochemical kinetics of nitroaromatics are increased significantly owing to their various long-range π-π stacking. Moreover, density-functional theory calculations further provide theoretical insights into the distinct electrochemical behaviors of the various nitroaromatics in the molecular level. This is the first study that reveals the influences of substituting groups and conjugated structures on the electrochemical performance of nitroaromatic cathode materials, which enables a functionoriented molecular design of such organic materials and sheds light on their future development.