Polycyclic Aromatic Hydrocarbons as a New Class of Promising Cathode Materials for Aluminum‐Ion Batteries

Abstract

As an emerging post-lithium battery technology, aluminum ion batteries (AIBs) have the advantages of large Al reserves and high safety, and have great potential to be applied to power grid energy storage. But current graphite cathode materials are limited in charge storage capacity due to the formation of stage-4 graphite-intercalated compounds (GICs) in the fully charged state. Herein, we propose a new type of cathode materials for AIBs, namely polycyclic aromatic hydrocarbons (PAHs), which resemble graphite in terms of the large conjugated π bond, but do not form GICs in the charge process. Quantum chemistry calculations show that PAHs can bind AlCl 4À through the interaction between the conjugated π bond in the PAHs and AlCl 4 À , forming onplane interactions. The theoretical specific capacity of PAHs is negatively correlated with the number of benzene rings in the PAHs. Then, under the guidance of theoretical calculations, anthracene, a three-ring PAH, was evaluated as a cathode material for AIBs. Electrochemical measurements show that anthracene has a high specific capacity of 157 mAh g À 1 (at 100 mA g À 1 ) and still maintains a specific capacity of 130 mAh g À 1 after 800 cycles. This work provides a feasible "theory guides practice" research model for the development of energy storage materials, and also provides a new class of promising cathode materials for AIBs.

Molecular-Scale Elucidation of Ionic Charge Storage Mechanisms in Rechargeable Aluminum–Quinone Batteries

“…Thus far, there have been a small number of studies on organic positive electrodes with aluminum (Al) metal, − with a focus on quinone-based molecules, though the nature of the electroactive ions is still poorly understood. Kim et al performed the first investigation of discrete organic molecules for Al batteries using an organic phenanthrene quinone (PQ) macrocycle where they proposed monovalent AlCl 2 + as the electroactive ion via a combination of time-of-flight secondary ion mass spectrometry (TOF-SIMS) and energy-dispersive X-ray (EDX) spectroscopy .…”

Tuning the Structure and Properties of N‐doped Positively Charged Polycyclic Aromatic Hydrocarbons

“…Polycyclic aromatic hydrocarbons (PAHs) display unique molecular geometries, electronic, optical and magnetic properties, making these compounds suitable for applications in organic electronics, photonics, spintronics, and energy storage. [1][2][3][4][5][6] In addition, PAHs are an important subject in environmental and astrochemistry. [7][8][9] Müllen and his coauthors have successfully implemented a bottom up approach for the synthesis of large PAHs.…”

“…This way, the heteroatom doping significantly changes the geometry, electronic and solubility properties with respect to the parent PAH molecule. Although, N-doped positively charged PAHs have been synthesized more than thirty years ago, [19] the interest for such systems started growing after Müllen and his coauthors [20] have shown that the arrangement of 9-phenyl-benzo [1,2]quinolizino [3,4,5,6-fed]phenanthridinylium in superstructures can be modulated by choosing proper anions. The synthesis, self-assembly and electronic properties of ionic N-doped PAHs have attracted much attention in recent years.…”

The COMPAS Project: A Computational Database of Polycyclic Aromatic Systems. Phase 1: cata-condensed Polybenzenoid Hydrocarbons

“…[6][7][8][9][10] In addition, PASs can function as platforms for electrocatalysis, 11 redox-active materials, 12 and organic electrode materials. 13,14 The development of improved organic electronic devices, such as light emitting diodes (OLEDs), 15 field effect transistors (OFETs), 5,16,17 solar cells (OSCs), 2,8 sensors, 18 and semiconductors 10,16,17,19 hinges on the design of new functional PASs. With the decreasing cost of computational resources and the concurrent advent of machine-learning (ML) and deep-learning (DL) techniques, data-driven design of molecules and materials for various uses has become an increasingly promising approach.…”