CuS loaded on reduced graphene oxide prepared by ball milling method as cathode material for high- power aqueous Cu-Al hybrid-ion batteries

Aqueous hybrid-ion batteries (AHBs) are a potential low-cost, high safety, high operating voltage and high energy density storage devices. A new type of AHBs was proposed. We use a simple, low-cost and energy-saving ball milling method for the synthesis of material that CuS anchored on reduced graphene oxide (CuS@rGO). Aqueous Cu-Al hybrid-ion batteries were prepared with CuS@rGO as cathode, Cu as anode and LiCuAl (LiCl, CuCl and AlCl3) aqueous solution as electrolyte. The battery produces a reversible capacity of 218.9 mAh g−1 at 2 A g−1. At a high current density of 5 A g−1, the capacity can also reach 166.7 mAh g−1 and the battery capacity retention rate is as high as 80% after 500 cycles. The successfully prepared CuS@rGO has excellent rate capability and strong cycling stability at high current density, which exceeds most reported aqueous and nonaqueous systems of Aluminum-ion batteries. The introduction of reduced graphene oxide (rGO) can accelerate the electron transfer in composites and provide better electrochemical kinetics, so it is conducive to the rapid storage of aluminum ions.