Organometallic structure-based βCD@FeSe2/CoSe2 heterostructures cathodes for high-performance aluminum-ion battery

Rechargeable aluminum ion batteries (AIBs) are gaining more and more attention because of their advantages such as high theoretical energy density, high safety, and reasonable price. However, the development of cathode materials for aluminum batteries has been one of the important bottlenecks limiting their development. Although many studies on cathode materials for AIBs have been reported, few of them have addressed the problems of poor cycling stability and low specific capacity of AIBs. Herein, a three-dimensional metal-organic structure electrode material covered with iron-cobalt selenide using cyclodextrin polymer (βCD) was synthesized. By changing the selenization temperature, βCD@FeSe, βCD@FeSe2/CoSe2, βCD@FeCo2Se4 were synthesized at 400 °C, 600 °C and 800 °C, respectively. AIBs based on βCD@FeSe2/CoSe2 heterostructured materials as cathodes exhibited excellent initial discharge specific capacity, showing 193 mAh g−1 at 1 A g − 1 and maintaining 167 mAh g−1 after 2200 cycles, with a capacity retention rate of 86.53 %. This was attributed to the stability of the βCD and the surface modification provided by the FeSe2/CoSe2 heterostructure. This work opens up a new direction in researching cathode materials for AIBs with high cycle performance and high capacity potential while providing a more reliable basis for the commercial application of AIBs.