Low cost and green preparation process for α-Fe2O3@gum arabic electrode for high performance sodium ion batteries

Abstract

Conventional electrode manufacturing processes for lithium ion batteries involve the use of toxic organic solvents (such as N-methyl-2-pyrrolidone, NMP). A low cost and green preparation process for high performance electrodes for sodium ion batteries (SIBs) is important to address simultaneously the environmental and health risks of production processes and the shortage of lithium metal. Herein, gum arabic (GA), which is a non-toxic biodegradable biopolymer, is used as a water soluble binder to design a water-based electrode preparation process to fabricate α-Fe₂O₃ electrodes (i.e., α-Fe₂O₃@GA electrode). The α-Fe₂O₃@GA electrode demonstrates better mechanical properties and binding capability than that of the α-Fe₂O₃ electrode with poly(vinylidene fluoride) (PVDF) as the binder (α-Fe₂O₃@PVDF electrode). Due to these merits, a higher rate and cycling performance of the α-Fe₂O₃@GA electrode are achieved compared with the α-Fe₂O₃@PVDF electrode when both electrodes are used for SIBs' application. The α-Fe₂O₃@GA electrode demonstrates high initial discharge and charge capacities of 2437 and 1102 mA h g⁻¹ at the current density of 0.2 A g⁻¹. The α-Fe₂O₃@GA electrode maintains a high reversible discharge capacity of 492 mA h g⁻¹ at the current density of 5 A g⁻¹ after 500 cycles with a fading rate of 0.08% per cycle after the first cycle, which indicates a superior cycling performance. The outstanding performance of the resultant SIBs suggests that the green fabrication process of the α-Fe₂O₃@GA electrode would play a critical role in the future battery industry.