Oxygen-Enriched α-MoO_3–x nanobelts suppress lithium dendrite formation in stable lithium-metal batteries

In this study, MoO₃ nanobelts (MNBs) are passivated on lithium (Li) metal anodes to suppress Li dendrite formation and, thereby improve the stability in Li-metal batteries. MoO₃ powder is ground into MNBs using a commercially viable mechanical grinding technique. The MNBs are then coated on Li metal using a simple spray-coating technique. The MNBs on top of the pristine Li mitigates the formation of Li dendrites by generating a uniform Li⁺ ion flux and providing shorter diffusion pathways. This facile passivation strategy prevents the growth of undesirable dendrites on pristine Li surfaces. A live transparent Li–Li symmetrical cell having MoO₃-coated Li anode (MNB-Li) does not form any Li dendrites and undergoes minimal surface degradation relative to that of the corresponding pristine Li cell. The Li–Li symmetrical cells featuring the MoO₃-coated surface operate with a low overpotential of approximately 18 mV for an extremely long period of time (ca. 2500 h) at a current density of 1 mA cm⁻². A Li–sulfur battery featuring the MNB-Li at 0.5 C significantly improves stability, with an initial capacity of 1127 mAh g⁻¹, a capacity of 820 mAh g⁻¹ for up to 200 cycles, and an excellent coulombic efficiency of 98.12 %.