Hydrothermal Synthesis of Nanoflake-Assembled (Ni0.5Co0.5)0.85Se Microspheres as the Cathode and Reduced Graphene Oxide/Porous Fe2O3 Nanospheres Composite as the Anode for Novel Alkaline Aqueous Batteries

The exploitation of new energy storage systems has gradually drawn researchers' interests in recent years. Herein, a novel alkaline aqueous battery is fabricated based on nanoflake-assembled (Ni0.5Co0.5)(0.85)Se microspheres and reduced graphene oxide (rGO)/porous Fe2O3 nanospheres composite as the cathode and anode, respectively. The nanoflake-assembled (Ni0.5Co0.5)(0.85)Se microspheres are prepared through a two-step hydrothermal approach, while the rGO/porous Fe2O3 nanospheres composite is synthesized by a facile one-pot ionic liquid-assisted hydrothermal approach. On account of the unique structural features as well as excellent electrochemical behaviors, the assembled novel (Ni0.5Co0.5)(0.85)Se//rGO/Fe2O3 alkaline aqueous battery achieves a great specific energy of 37.2 W h kg(-1) at a power density of 500 W kg(-1) or an ultrahigh specific power of 10 kW kg(-1) at a reasonable specific energy of 11.9 W h kg(-1) and excellent cycling performance with 84.5% of initial capacity retention at 3 A g(-1) after 2000 cycles. These intriguing results suggest that the reasonable design and coupling of the cathode and anode are crucially significant for fabricating high-performance energy storage systems. Such an alkaline aqueous battery is expected to be one of highly prospective energy storage systems for practical applications.