Designing the Binder-Free Conversion-Based Manganese Oxide Nanofibers as Highly Stable and Rate-Capable Anode for Next-Generation Li-Ion Batteries

Recently, manganese (Mn)-based oxides have attracted more attention as a promising anode material for the next-generation lithium-ion batteries (LIBs) because of their higher experimental capacity, abundance, cost-effectiveness, and environmental-friendly nature. However, the poor rate capability and rapid capacity fading caused by the volume fluctuations during cycling hamper their usage in practical applications. To address these concerns, we report one-dimensional, high-aspect ratio MgMn2O4 (MMO) nanofibers with morphological voids/gaps as a binder-free negative electrode for LIBs. Herein, the binder-free electrodes of MMO nanofibers are fabricated via facile electrophoretic deposition technique. They can provide a well-designed network between the active materials and current collector, which enhances the electrical conductivity and Li-ion diffusion by avoiding binders as dead mass, which in turn helps to increase the energy density of LIBs. Furthermore, the morphological voids in between the individual nanoparticles of MMO nanofibers and the inactive MgO matrix element act as a buffering space that effectively accommodates the volume variation during lithiation and delithiation processes. The MMO nanofibers as LIB anodes exhibit a high reversible specific capacity of 776 mA h g(-1) at 0.1 C after 125 cycles and good cyclic stability (609 mA h g(-1) at 2 C after 600 cycles) with similar to 99.3% capacity retention. Moreover, the binder-free MMO nanofiber anode also exhibits an ultrahigh rate capability (215 mA h g(-1) at 9 C) that is generally difficult to attain in conversion-based materials. The excellent electrochemical performances can be ascribed to the 3D microstructure of the fabricated electrode and one-dimensional porous nanofabric morphology of MMO, which can ensure fast ion and electron transportation. Considering the excellent Li storage performance, the binder-free MMO nanofiber-based electrodes are expected to be promising anodes for next-generation LIBs.

Automated summary

Researchers have developed a novel binder-free magnesium manganese oxide nanofiber for lithium-ion batteries, which exhibits excellent electrochemical performance, high energy density, and good cyclic stability.