Based on the utilization of jarosite residue: The lithium storage performance of α-Fe2O3 materials synthesized from different iron solution systems

Abstract

• The anion in iron salt has a great impact on the morphology of the prepared α -Fe 2 O 3 . • α -Fe 2 O 3 prepared from sulfate has a high capacity but large fluctuations. • α -Fe 2 O 3 prepared from chloride shows a low capacity but good cycling stability. In this work, three kinds of iron simulation solution systems (FeCl 3 , FeSO 4 , and Fe 2 (SO 4 ) 3 solutions) are prepared and used as an iron source for synthesizing α -Fe 2 O 3 electrode materials by the one-step sucrose-assisted thermal decomposition method. The microstructure and lithium storage performance of the as-prepared α -Fe 2 O 3 materials are systematically studied by XRD, SEM, TGA, FT-IR, XPS, CV, EIS, and discharge/charge measurements. The results demonstrate that the α -Fe 2 O 3 samples prepared from FeSO 4 simulation solution or Fe 2 (SO 4 ) 3 simulation solution are composed of interconnected nanorods particles and contain a certain amount of undecomposed SO 4 2− ; while the α -Fe 2 O 3 sample prepared from FeCl 3 simulation shows irregular particle morphology (with the size ranging from hundreds of nanometers to several microns) and contains a small amount of Cl − . The two α -Fe 2 O 3 samples prepared from sulfate simulation solution exhibit high lithium storage activity but experience large capacity fluctuation during cycling. In contrast, the α -Fe 2 O 3 sample prepared from the FeCl 3 simulation solution gives a lower reversible capacity but much better cycling stability. After 400 cycles at 500 mA g −1 , the α -Fe 2 O 3 samples prepared from FeSO 4 , Fe 2 (SO 4 ) 3 , and FeCl 3 simulation solutions deliver reversible capacities of 947, 1071, and 628 mA h g −1 , respectively. The results reported in this work could provide clues for the structural design and performance modification of Fe-based oxides as anode materials for lithium-ion batteries.