Metal-Organic Framework Structure with Fe-Co-Se (MIL-88A/Fe-Co@Se) as a Cathode for Aluminum Batteries

Rechargeable aluminum-ion batteries have received more and more attention because of their high theoretical energy density, high safety, and reasonable price. The cathode material of aluminum batteries is one of the key bottlenecks that limits their development. Although there are many reports on aluminum battery cathode materials, many of these reports fail to simultaneously solve the poor cycling stability and low specific capacity of aluminum batteries. Therefore, we formed YSNT@Se hybrids by compounding the MOFs─MIL-88A@Fe-Co hydroxide yolk-shell nanotubes (YSNTs) with selenium for the first time. It was finally determined that the FeSe₂ in YSNT@Se is the main redox reaction participant during charging/discharging. In the charge/discharge of YSNT@Se 500 °C, it achieved a first cycle discharge specific capacity of 292.21 mA h g^-1. After 500 cycles, the discharge capacity was 233.34 mA h g^-1 and the capacity retention rate reached 79.85%. This result proves that the redox process is highly reversible at the same time. This work makes it possible for aluminum batteries to have a high cycling performance and a high capacity and broadens the research direction of cathode materials for aluminum batteries.