Flexible electrode for long-life rechargeable sodium-ion batteries: effect of oxygen vacancy in MoO3−x

Abstract

Layered molybdenum trioxide (MoO₃) has rarely been studied as an electrode material for sodium ion batteries due to its low electronic conductivity and irreversible phase transitions. Here we demonstrate that MoO_3−x, with a well-controlled oxygen vacancy, exhibits near theoretical capacity, excellent rate capability, and 2000 stable cycles with minimal capacity loss. The oxygen vacancy in MoO_3−x is responsible for the two-plateau voltage profile, in contrast to the sloping feature observed in α-MoO₃. This work highlights the importance of oxygen vacancies in enabling long-life rechargeable sodium-ion batteries.