Li-ion storage in orthorhombic hydrated sodium molybdate with oxygen-vacancy defects

Two orthorhombic salts (OHMs) of Na2MoO4⋅(H2O)2 were prepared at 130 °C (OHMs_130) and 170 (OHMs_170) via a hydrothermal process, followed by heat treatment. Advanced analyses proved the formation mechanism layered structures unique OHMs. All OHMs possessed with many empty channels numerous oxygen vacancies (VO). VO formed due to absence O atoms in tetrahedra MoO4 (Vsh-O) loss H2O molecules (Vwater-O) structure. Despite micro-sizes crystals, OHMs-based anodes Li-ion batteries exhibited superior cyclic rate performance. OHMs_170 electrode higher capacity retention (91.6% after 200 cycles) capability (80% 3 A g−1) than OHMs_130. It is attributed advantageous amount Vwater-O low Vsh-O leading stable structure electrodes fast Li+ ion movements during charge/discharge processes. In addition, electrochemical impedance spectroscopy, Randles-Sevcik equation, kinetic study results suggested that exceptional performance came from resistance, pseudo behavior, mobility inside