A space-confined strategy towards stable α/β-Bi2O3 heterojunction anode for high-energy aqueous battery

Abstract

It is very necessary to design a high-capacity and stable Bi2O3 anode for nickel-bismuth (Ni//Bi) batteries. In this work, a stable α- and β- phase Bi2O3 heterojunction nanocomposite (α/β - Bi2O3) was successfully prepared via a simple “space-confined” strategy and it was used as a superior anode for nickel-bismuth (Ni//Bi) battery. The α/β-Bi2O3 obtained by using MCM-41 as a space-confined template possesses a stable structure and enhanced charge transfer capability. Such superior traits vest the designed α/β-Bi2O3 electrode with high specific capacity (235 mAh g−1 at 1 A g−1), extraordinary rate performance (137 mAh g−1 at 40 A g−1, and ∼58% capacity retention vs 1 A g−1), and excellent cyclic durability (75% capacity retention after 5000 cycles). Such performances are far superior to that of mono-phase α-Bi2O3 and β-Bi2O3 electrodes. Furthermore, an excellent Ni//Bi battery with outstanding energy density (∼155 Wh kg−1) and long cycle life was assembled using the obtained α/β-Bi2O3 electrode and a NiC2O4 electrode as anode and cathode, respectively (NiC2O4//α/β-Bi2O3). This work opens a new alternative strategy for the rational design of efficient electrodes for reliable aqueous rechargeable batteries.