Heterostructure Engineering for Aluminum-Ion Batteries: Mechanism, Challenge, and Perspective.

Benefiting from high volumetric capacity, environmental friendliness, and high safety, aluminum-ion batteries (AIBs) are considered to be promising battery system among emerging electrochemical energy storage technologies. As an important component of AIBs, the cathode material is crucial to decide the energy density and cycle life of AIBs. However, single-component cathode materials are unable to achieve a balance between cycling stability and rate performance. In recent years, research on heterostructure cathode materials has gained significant attention in AIBs. By harnessing the synergistic effects of heterostructure, the shortcomings of individual materials can be overcome, contributing to improved conductivity and structural stability. This review offers a detailed insight into the Al-storage mechanism of heterostructure cathodes, and provides an overview of the current research progresses on heterostructure cathode materials for AIBs. Starting from the relationship between the microstructure and electrochemical performance of heterostructure materials, the different structure design strategies are elaborated. Besides, the challenges faced by heterostructure are summarized, and their potential impact on the future of the energy storage industry is anticipated. This review provides the guidelines for the future research of heterostructure as cathode materials for AIBs.