Enhancing electrochemical performance of Fe2O3 via in situ sulfurization and carbon coating modification for nickel-iron rechargeable batteries.

Abstract The passivation issue of Fe 2 O 3 electrode has triggered off their low practical capacity, poor rate capability and cycling performance and thus limited their practical application as anodes for alkaline Ni-Fe batteries. This paper proposes a dual modification of Fe 2 O 3 by in-situ sulfurization and post carbon coating. Fe 2 O 3 -S nanorod arrays with a uniform sulfurization layer coated on Fe 2 O 3 core were firstly fabricated by in-situ sulfurization of Fe 2 O 3 nanorod arrays grown on Ti foil. After coating carbon on the Fe 2 O 3 -S arrays by PECVD process, Fe 2 O 3 -S@C were obtained. Electrochemical tests in alkaline electrolyte in the potential window of −1.2∼0 V show that the Fe 2 O 3 -S@C exhibited dramatically improved discharge capacity (60.5 times compared to Fe 2 O 3), cycling stability (92.2% for Fe 2 O 3 -S@C and only 7.9% for Fe 2 O 3 -S after 100 cycles) and excellent rate capability, owing to the co-contribution of the sulfurization layer and carbon layer. Furthermore, a Ni-Fe cell is assembled by pairing with a Ni 2 S 3 cathode, and delivers high energy/power density (45.64 Wh/kg at 1.3 kW/kg and 27.14 Wh/kg at 10.3 kW/kg). [ABSTRACT FROM AUTHOR]