Core-Bishell Fe-Ni@Fe3O4@C Nanoparticles as an Advanced Anode for Rechargeable Nickel-Iron Battery

Developing high performance iron electrodes is still challenging for nickel-iron batteries. In the present work, we reported a novel core-bishell Fe-Ni@ Fe3O4@ C nanoparticle for the first time as an advanced iron electrode. XRD and HRTEM results revealed that Fe3O4 nanoparticle partially converted to Fe-Ni alloy after the incorporation of nickel source, forming the core-bishell FeNi@ Fe3O4@ C structure. When used as an anode for nickel-iron batteries, Fe-Ni@ Fe3O4@ C with an appropriate amount of Ni modification exhibited significantly improved electrochemical performance. It showed a stable discharge plateau at about 1.1 V, while the bare one had no obvious plateau. A much higher discharge capacity of 340 mAh g-1 was also exhibited at 1 A g-1 and it maintained 312 mAh g-1 after 100 cycles, indicating excellent cycling stability for Fe-Ni@ Fe3O4@ C. The superior electrochemical properties of the Fe-Ni@ Fe3O4@ C sample should be mainly related to the improved electronic conductivity and decreased ion transfer resistance in comparison with the bare Fe3O4/C. (C) 2017 The Electrochemical Society. All rights reserved.