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

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 pi bond, but do not form GICs in the charge process. Quantum chemistry calculations show that PAHs can bind AlCl4 through the interaction between the conjugated pi bond in the PAHs and AlCl4- forming on-plane 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 mAhg(-1)( )(at 100 mA g(-1)) and still maintains a specific capacity of 130 mAhe 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.

Automated summary

Aluminum ion batteries (AIBs) have potential for energy storage, but current graphite cathode materials are limited. A new type of cathode materials, polycyclic aromatic hydrocarbons (PAHs), specifically anthracene, show high specific capacity and cycle stability, providing a promising option for AIBs.