High performances aqueous nickel-bismuth batteries assembled with highly crystalline Bi2O3 and CoNi-CoNiO ₂ @NiCo layered double hydroxides heterostructure nanoarrays

Bi2O3 as prospective anode active materials for aqueous rechargeable nickelbismuth batteries, is confronted with limited capacity and cycling durability.Herein, highly crystalline Bi2O3 with a tousled, cookie-like microstructure was synthesized by calcining Bi2O2CO3 precursors.The as-prepared Bi2O3 delivers a remarkable specific capacity of 266.7 mAh/g at 2 A/g and 203.3 mAh/g at 20 A/g, while maintaining 62.6% of its initial capacity after 1900 cycles at 15 A/g.For the cathode, heterostructured nanoarrays consisting of CoNiO2 and Co-Ni alloy cores grown on nickel foam, coated with nickel-cobalt layered double hydroxide shells, exhibit excellent electrochemical performance, with specific capacities of 249.7 mAh/g at 1 A/g and 112.0 mAh/g at 20 A/g.The assembled aqueous nickel-bismuth battery achieves a maximum energy density of 34.8 Wh/kg and a power density of 4400.5 W/kg at 1 A/g.These outstanding energy storage properties are attributed to the synergistic effect of the highly crystalline, tousled Bi2O3 anode and the heterostructured nanoarray cathode.