Developing high-rate and durable anode materials for sodium-ion batteries (SIBs) is still a challenge because of the larger ion radius of sodium compared with the lithium ion during charge–discharge processes.

Single-crystal-to-single-crystal (SCSC) transformations provide more possibilities for phase transitions, which have attracted great attention in crystal engineering. In this paper, we report a series of reversible SCSC transformations between nanoscale two-dimensional layered double hydroxide (LDH) crystals and three-dimensional metal–organic framework crystals. They can proceed not only in solution systems but also on the surface of solid-state polyacrylonitrile films and fibers. Specifically, reversible SCSC transformations can be carried out between nanoscale ZIF-67 and Co-LDH. The Co-LDH nanomaterials displayed excellent oxygen evolution reaction performance. This work has good universality and scalability, which provides a novel avenue for the synthesis of crystal materials and is of great significance for the recycling of resources.

Transition metal chalcogenides (TMCs) have been widely explored and utilized in sodium-ion battery (SIB) anodes due to their unique advantages such as high theoretical specific capacity and low cost. However,...