Anchoring V2O5 nanosheets on hierarchical titanium nitride nanowire arrays to form core–shell heterostructures as a superior cathode for high-performance wearable aqueous rechargeable zinc-ion batteries
Fiber-shaped Zn-ion batteries (ZIBs) have attracted enormous attention as an efficient means of energy storage for next-generation portable and wearable electronic devices due to their low cost, light weight, environmental friendliness, tiny volume, extraordinary weaveability, and excellent safety characteristics. However, their low energy density and poor rate capability and cycling performance continue to restrict their rapid development. In this study, we developed three-dimensional well-aligned titanium nitride (TiN)@V2O5 nanowire arrays (NWAs) with a hierarchical core–shell heterostructure directly grown on carbon nanotube fibers (CNTFs) as the binder-free cathode for fiber-shaped ZIBs. The TiN@V2O5 NWA/CNTF cathode benefits from the synergistic merits of layered V2O5 nanosheets and highly conductive TiN NWAs and exhibits remarkable Zn-ion storage performance, with a high capacity of 1.45 mA h cm−2 (636.0 mA h g−1) at 0.5 mA cm−2 and a high rate capability of 1.11 mA h cm−2 (486.8 mA h g−1) at 10 mA cm−2. Meanwhile, the as-assembled all-solid-state fiber-shaped ZIBs can deliver a high capacity of 405 mA h cm−3 (1.215 mA h cm−2 or 532.9 mA h g−1) at 0.5 mA cm−2, a high energy density of 283.5 mW h cm−3 (373.0 W h kg−1), an outstanding cycling life of up to 3500 cycles, and a capacity retention of 90.6%. More importantly, these fiber-shaped ZIBs have excellent flexibility and integration features. The choice of the cathode material, TiN@V2O5 NWAs, introduces a new prospect for the design of high-performance aqueous rechargeable fiber-shaped ZIBs for portable and wearable electronics.