Bimetallic Borate Ni2FeBO5 as a High-Performance Anode for Sodium-Ion Batteries

Due to the advantages of low cost and abundant resources, sodium-ion batteries have great potential in the development of next-generation energy storage batteries. In this work, we designed and synthesized bimetallic borate Ni2FeBO5 with reference to the ion doping modification method to overcome the frequent problem of rapid capacity decay of traditional single-metal borate as anode for sodium-ion batteries (SIBs). The Ni2FeBO5 composite exhibits an initial charge capacity of 428 mAh g–1, retaining favorable cycling property (171 mAh g–1 for 150 cycles at 100 mA g–1) and good rate performance (126 mAh g–1 at 3200 mA g–1). The reasons for capacity degradation were systematically analyzed using ex situ scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS), and galvanostatic intermittent titration technique (GITT).