Synthesis Design of Bimetallic Selenide NiCoSe₂@F-Doped C with Core–Shell Structure as Cathode for Advanced Rechargeable Aluminum Batteries

Rechargeable aluminum batteries (RABs) have been considered as a potential candidate for next-generation energy storage systems because of their high security, abundant resources, and high specific capacity. However, the poor cycling performance and sluggish reaction kinetics hinder the practical application of RABs. In this paper, an electrode material of NiCo bimetallic selenide nanospheres embedded in fluorine-doped carbon (NiCoSe2@F-C) has been designed for enhancing electrochemical performance. NiCoSe2@F-C doping with heterogeneous elements presented a stable core–shell structure and large surface area, playing a significant role in improving the cycling ability, specific capacity, and electrochemical reaction kinetics for RABs. The RABs based on NiCoSe2@F-C cathode exhibit high reversible capacity (294 mAh g–1 at 0.5 A g–1) and excellent cycle performance (115 mAh g–1 at 1 A g–1 over 400 cycles). It is confirmed that the charge storage mechanism of the NiCoSe2@F-C electrode is the intercalation/deintercalation of AlCl4– with the charge/discharge processes jointly controlled by capacitance and diffusion. This work provides an effective approach for further developing advanced cathodes of RABs with excellent electrochemical performance.