α-Fe2O3 with novel double hexagonal pyramid morphology synthesized using a dual-ion co-work system as an anode for lithium-ion batteries

Abstract

In this study, α-Fe₂O₃ particles with novel double hexagonal pyramid morphology were synthesized via a facile hydrothermal method in a rare system of coexisting ammonium ions (NH⁴⁺) and carbonate ions (CO₃²⁻), which was different from the previously used single-ion inducing system. A series of experimental results indicated that the synergistic effects of NH⁴⁺ and CO₃²⁻ played a decisive role in the formation process of α-Fe₂O₃ particles with the unique morphology, and the formation mechanism was attributed to the oriented aggregation and Ostwald ripening process. When utilized as anode materials for LIBs, the α-Fe₂O₃ particles with the double hexagonal pyramid morphology exhibited the excellent cycling stability of 700 mA h g⁻¹ after 100 charge/discharge cycles with the high coulombic efficiency of 98% starting from the 25th cycle; this indicated that these particles could be a promising alternative anode for LIBs.