Atomic-level defect engineering enables hollow ternary molybdenum phosphoselenide nanospheres for enhanced sodium-ion storage

Transition-metal phosphides (TMPs), as promising anode materials for sodium-ion batteries (SIBs), offer high theoretical capacity and low redox potential, but the key issues of actually poor stability and sluggish kinetics upon cycling hinder their practical application. Herein, we present a reliable approach to address these challenges by fabricating a single-phase ternary molybdenum phosphoselenide compound (MoPSe/NC), which holds multiple advantages for Na-ion storage, including a rich defect structure, enlarged interlayer spacing, and chemical bonding interaction (Mo-C and C-Se bonds), which collectively enhance both reaction kinetics and structural stability. Systematic electrochemical investigations reveal that incorporating Se into MoP to regulate the phase structure induces the formation of abundant anion defects, leading to increased active sites and optimized Na + diffusion pathways for faster ion storage kinetics. As an anode, the MoPSe/NC delivers a high specific capacity of 450 mAh g −1 at 0.1 A g −1 and an outstanding cycling lifespan, retaining 83.3 % of its capacity after 800 cycles at 1 A g −1 . Notably, the assembled full-cell with a Na 3 V 2 (PO 4 ) 3 cathode achieves a high energy density of 180.4 Wh kg −1 . This novel design strategy provides a straightforward path for the development of TMPs, contributing to the advancement of high-performance SIBs.