An insight into the electrochemical performance of lithium-ion battery anodes via an O/N bifunctional group strategy in Janus MoB

Abstract

Two-dimensional (2D) Janus-structured MoB, asymmetrically functionalized with O and N groups, is engineered as a high-performance anode material for LIBs, addressing the intrinsic limitations of pristine MoB through rational surface modulation. Leveraging first-principles calculations, this study systematically investigates the synergistic effects of O/N functionalization on the electronic structure, adsorption behavior, ion transport kinetics and the like. The Janus architecture induces a polarized interfacial charge distribution due to the electronegativity contrast between O (3.44) and N (3.04), which homogenizes Li adsorption energies and reduces diffusion barriers ((0.47 eV (O-terminated) and 0.49 eV (N-terminated)), enabling ultrafast Li-ion migration. The optimized surface environment achieves a theoretical specific capacity of 587 mA h g⁻¹. Remarkably, the open circuit voltage (OCV) stabilizes within the 0–1 V window, thermodynamically inhibiting Li dendrite nucleation, while lattice distortion remains minimal (<3.6% area strain) during cycling, ensuring structural integrity. These advances are attributed to the synergistic effect of O/N groups: (1) preventing metal atom leakage via surface modification, (2) homogenizing ion transport through interfacial charge engineering, (3) the electronegativity and atomic radius differences induce charge polarization, enhancing adsorption stability. The work establishes a universal design strategy for Janus-type MBenes, emphasizing the critical role of asymmetric functionalization in balancing surface adsorption and diffusion kinetics. By correlating atomic-scale charge redistribution with macroscopic electrochemical performance, this contribution provides foundational insights for synthesizing high-performance LIB anodes. Additionally, it offers a theoretical roadmap for experimental synthesis, accelerating the development of next-generation 2D materials tailored to energy storage applications.