EDTA-2Na assisted dynamic hydrothermal synthesis of orthorhombic LiMnO2 for lithium ion battery.

Herein, pure orthorhombic LiMnO 2 (o-LiMnO 2) was prepared via a one-step and short time EDTA-2Na assisted dynamic hydrothermal method, in which the electrolytic MnO 2 and C 4 H 6 MnO 4 ·4H 2 O were used as manganese source. The effects of EDTA-2Na concentration, hydrothermal temperature and stirring rate on the purity of o-LiMnO 2 were investigated. EDTA-2Na served as both chelating reagent and reductant, the oxidation of Mn2+ before reaction and the formation of Li 2 MnO 3 by residual oxygen in reaction system were suppressed due to coordination and reduction effects of EDTA-2Na, respectively. Furthermore, the solid-liquid reaction kinetics could be accelerated by stirring, then final expected pure phase o-LiMnO 2 was generated in short time and a low alkali concentration. The obtained product showed high crystallinity with an average diameter of 200–500 nm. When utilized as a lithium ion battery cathode material, the o-LiMnO 2 could deliver a high capacity of 166.1 mAh g−1 at 0.1 C at the voltage range of 2.0–4.5 V. • The pure orthorhombic LiMnO 2 can be prepared via a facile one-step dynamic hydrothermal method with MnO 2 as precursor. • EDTA-2Na serves as both chelating reagent and reductant in reaction system to minimize the impurities in final product. • o-LiMnO 2 delivers initial capacity of 166.1 mAh g−1 at 0.1 C and achieves 87% capacity retention rate after 50 cycles. [ABSTRACT FROM AUTHOR]