One-pot interfacial engineering of ZnMn₂O₄/N-rGO nanocomposites as anode materials for high-performance lithium-ion batteries

Abstract

In recent years, spinel-structured transition-metal oxide ZnMn₂O₄ has attracted attention as a low-cost anode material with high lithium-ion storage capacity. However, its practical application is limited by poor intrinsic electrical conductivity, sluggish reaction kinetics, and large volume changes during repeated lithiation and delithiation, leading to unstable cycling behavior. Although several strategies have been explored to improve cyclic stability, many reported systems still suffer from limited rate performance, multistep synthesis routes, and an incomplete understanding of nitrogen-doped graphene oxide (N-rGO)-induced interfacial effects. In this work, hybrid ZnMn₂O₄/N-rGO nanocomposites with controlled graphene oxide additions of 20 and 30 wt% were synthesized via a simple one-pot hydrothermal route, enabling intimate oxide–N-rGO interfacial contact. Structural, microscopic, and X-ray photoelectron spectroscopy analyses confirmed the formation of phase-pure tetragonal ZnMn₂O₄ nanoparticles uniformly distributed on the N-rGO framework. XPS revealed a redistribution of nitrogen bonding configurations at higher GO loading, with increased graphitic nitrogen contribution that may enhance electronic conductivity, while pyridinic and pyrrolic nitrogen species provide interfacial active sites. Brunauer-Emmett-Teller analysis showed that increasing GO content enhanced the specific surface area and pore volume while preserving mesoporous architecture. The ZnMn₂O₄/N-rGO nanocomposite containing 30 wt% graphene oxide (ZMO-30) delivered a reversible discharge capacity of 859.02 mAh g^-1 after 100 cycles at 100 mA g^-1 with superior rate performance and reduced charge-transfer resistance, demonstrating the beneficial role of oxide–N-rGO interfacial engineering in improving the kinetics and durability of ZnMn₂O₄ anodes.