Defect-rich conversion-based manganese oxide nanofibers: An ultra-high rate capable anode for next-generation binder-free rechargeable batteries

Abstract

Recently, nanostructured materials with oxygen defects and their utilization as electrode materials for lithium-ion batteries (LIBs) are gaining considerable popularity. However, it is still unclear how surface morphology, nanostructuring, and oxygen defects contribute to Li-storage characteristics. In view of this, the present research work is focused on the fabrication of one-dimensional, porous, and oxygen-deficient nanofibers of MgMn2O4 (MMO) through electrospinning technique, followed by their subsequent heat-treatment on various temperatures such as 450 °C, 600 °C, and 750 °C. A quantitative analysis of oxygen defects indicates that MMO-600 contains a high number of oxygen vacancies. Further, the binder-free electrodes of all the samples are fabricated via electrophoretic deposition technology and their Li-storage performance is investigated. As a binder-free LIB anode, MMO-600 exhibits excellent reversible specific capacity, rate capability, and cyclic stability (817 mAh g−1 after 500 cycles at 2 C) with ∼ 99% coulombic efficiency. Further, MMO-600 displays the capacity of 228 mAh g−1 at 10 C is found to be better than the MMO-450 and MMO-750. Additionally, the feasibility of MMO-600 is also investigated in full cell configuration with a binder-free LiNi1/3Mn1/3Co1/3O2 cathode, which exhibited an energy density of 166 ( ± 3) Wh kg−1.