Reconstructing fast ion transport channels of Zn3V2O7 (OH)2.2H2O to realize enhanced Zn2+storage performance

Zinc ion batteries attract great attention because of their safety, economy and environmental friendliness. However, the sluggish diffusion kinetics of Zn2+ limit practical application. Here, reconstructed Zn3V2O7 (OH)2.2 H2O (ZVO) is prepared by electrochemical in situ conversion and the bridge oxygen vacancy concentration of V-O-V in ZVO is regulated by adjusting conversion conditions to modulate the ion transport channels. The Zn2+ diffusion energy barrier is minimized (0.20 eV) at a bridge oxygen vacancy concentration of 8%, while more oxygen vacancies hinder the transport of Zn2+ since the channel shrink. Thanks to the reconstructed one-dimensional channels with 8% V-O-V bridging oxygen vacancies, the cathode exhibits ultra-high performance of 135 mAh g-1 at 80 A g-1 and long life of 10,000 cycles with an 88% capacity retention at - 30 celcius.

Automated summary

Reconstructed Zn3V2O7 (OH)2.2 H2O (ZVO) with 8% V-O-V bridging oxygen vacancies was prepared to minimize the diffusion energy barrier of Zn2+ in zinc ion batteries. The cathode with 8% V-O-V bridging oxygen vacancies exhibited ultra-high performance of 135 mAh g-1 at 80 A g-1 and long life of 10,000 cycles with an 88% capacity retention at -30 celcius.