Nanoframes@CNT Beads-on-a-String Structures: Toward an Advanced High-Stable Sodium-Ion Full Battery

Engineering intriguing electrode with exceptional kinetics behaviors is imperative for boosting sodium storage systems. Herein, the uniform nanoframes are threaded by the interwoven carbon nanotube (CNT) conductive network to form an ingenious beads-on-a-string structured NiFePBA nanoframe/CNT (NFPB-NF/CNT) cathode and the corresponding derivative NiFeSe nanoframe/CNT (NFS-NF/CNT) anode. NFPB-NF/CNT exhibited remarkable cycling life along with outstanding rate capability and low voltage decay per cycle. The fast Na⁺ conduction and sufficient sodiation reaction is proved using Na⁺ diffusion models. Meanwhile, an exceptional sodium storage capacity and prolonged cycling life is achieved using binary NFS-NF/CNT anode at a high rate. In situ and ex situ investigations are used to reveal the sodium storage mechanisms and structural evolution process. Furthermore, a sodium-ion full battery based on the above electrodes shows stable performance accompanied by high energy conversion efficiency. The material design strategy provides a new solution for exploiting smart multicomponent composites toward advanced energy storage devices.