Self-sacrificed synthesis of conductive vanadium-based Metal–Organic framework nanowire-bundle arrays as binder-free cathodes for high-rate and high-energy-density wearable Zn-Ion batteries

Abstract

Metal-organic frameworks (MOFs) with adjustable structures and large surface areas are attracting ever-increasing attention in the field of next-generation energy storage. However, it still remains a great challenge to directly adopt MOFs as binder-free electrode materials resulting from their poor conductivity and form of bulk powders. Herein, we reported a novel self-sacrificed route to construct three dimensional conductive vanadium-based MOFs (V-MOFs, MIL-47) nanowire-bundle arrays on carbon nanotube fibers as advanced cathodes for aqueous Zn-ion batteries. Contributed by their abundant active sites, high conductivity, and hierarchical porosity, the assembled Zn-ion battery delivered a high volumetric capacity of 101.8 mAh cm−3 at a current density of 0.1 A cm−3 and an excellent rate capability (64.3% of initial capacity after a 50-fold increase in current density) in an aqueous electrolyte. More importantly, the assembled all-solid-state flexible fiber-shaped Zn-ion battery simultaneously exhibited both high energy density (17.4 mWh cm−3) and power density (1.46 W cm−3). Thus, this work demonstrates that the developed V-MOF is a promising candidate for cathode materials in Zn-ion batteries, paving the way for the construction of transition-metal-based conductive MOFs nanowires on current collectors for next-generation energy storage devices.