A topochemical reaction induced the formation of BiS micro-straws from a Bi-MOF for an ultra-long Zn storage life.

Aqueous zinc ion batteries (ZIBs) are considered as promising energy storage devices in the post-lithium-ion era, due to their high energy density, low cost, high safety, and environmental benignity, however their commercialization is hindered by the sluggish diffusion kinetics of cathode materials due to the large hydrate Zn radius. In this work, we propose a unique structure inheritance strategy for preparing BiS micro-straws in which a metal-organic framework (MOF) denoted as Bi-PYDC (PYDC = 3,5-pyridinedicarboxylate) with a string of [BiO] chains is judiciously selected as the structure-directing template to induce the formation of micro-straws based on a topochemical reaction. The distinctive hollow structure significantly enhances the ionic storage kinetics. Impressively, the obtained battery exhibits an ultra-long cycle life of more than 10 000 cycles at a current density of 1 A g while maintaining a capacity of more than 153.4 mA h g. In addition, the Zn insertion/extraction mechanism of BiS micro-straws is also investigated by multiple analytical methods, revealing the involvement of Zn rather than H in the electrochemical storage process. This work may lead a new direction for constructing high performance cathodes of Zn-ion batteries through a MOF-based structure-directing template.