Gallium regulated MnO2 toward high performance Zn ion batteries

alpha-MnO2 with open tunnel structure has received ever-increasing attention because of its superior specific capacity, yet generally undergoes unstable phase transition from the tunnel architecture to layered structure upon Zn2+ insertion as well as the disadvantages of low electrical conductivity and slow Zn2+ diffusion kinetics, thereafter triggering inactive reaction dynamics. In this regard, a gallium (Ga) doped alpha-MnO2 nanowires (denoted as MnO2-Ga) is firstly built in this work to address the abovementioned issue and the MnO2-Ga2 dis-plays enhanced performance with reversible capacity of 205.1 +/- 5 mAh g-1 undergoing 200 cycles at 0.2 A g-1. After repeated 2000 cycles at 1 A g-1, a capacity of 123.7 +/- 5 mAh g-1 can be still obtained. Validated by the theoretical calculation, it is noted that the Ga could effectively regulate the electronic distribution of alpha-MnO2 and narrows the bandgap, prompting the electronic cloud polarization of O and therafter accelerating ion diffusion efficiency. Fundamentally, the Ga intercalation results in the formation of Ga-O bonds. This special building not only guarantees the reversible phase transition and alleviates the Mn dissolution of Ga-MnO2, but also weakens the Zn2+-O2-interactions, leading to elevated cyclic durability and capacity.