Nano-Ni/Co-PBA as high-performance cathode material for aqueous sodium-ion batteries
Yunshu Zeng, Yuyuan Wang, Zhen Huang, Hongyu Luo, Han Tang, Shijie Dong, Ping Luo
Abstract
Abstract Prussian blue analogues (PBAs) are reliable and promising cathode materials for aqueous sodium-ion batteries (ASIBs) owing to their open three-dimensional frameworks, outstanding stability, and low production costs. However, PBAs containing only a single type of transition-metal ion often have limited charge-storage capacities in aqueous systems. This study reports the first example of K 0.11 Ni 0.39 Co 0.79 [Fe(CN) 6 ]·2.04H 2 O nanoparticles (Ni/Co-PBA) being used as a high-capacity cathode material for ASIBs. Owing to multi-electron redox reactions involving Co and Fe ions, Ni/Co-PBA has an initial capacity of 65 mAh g −1 and a capacity retention rate of 80% after 1000 cycles at 1.0 A g −1 , indicating its outstanding cycle performance and capacity retention. Ex-situ x-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and the galvanostatic intermittent titration technique were used to analyze the redox mechanisms and kinetics of Ni/Co-PBA. Ni/Co-PBA-based ASIBs are among the most promising energy-storage technologies for large-scale fixed energy-storage systems because of their outstanding electrochemical performance, low costs, and high efficiency.