Modified H2 V3 O8 to Enhance the Electrochemical Performance for Li-ion Insertion: The Influence of Prelithiation and Mo-Substitution

Abstract

Nanostructured H₂ V₃ O₈ is a promising high-capacity cathode material, suitable not only for Li⁺ but also for Na+, Mg²⁺ , and Zn²⁺ insertion. However, the full theoretical capacity for Li⁺ insertion has not been demonstrated experimentally so far. In addition, improvement of cycling stability is desirable. Modifications like substitution or prelithiation are possibilities to enhance the electrochemical performance of electrode materials. Here, for the first time, the substitution of vanadium sites in H₂ V₃ O₈ with molybdenum was achieved while preserving the nanostructure by combining a soft chemical synthesis approach with a hydrothermal process. The obtained Mo-substituted vanadate nanofibers were further modified by prelithiation. While pristine H₂ V₃ O₈ showed an initial capacity of 223 mAh g^-1 and a retention of 79 % over 30 cycles, combining Mo substitution and prelithiation led to a superior initial capacity of 312 mAh g^-1 and a capacity retention of 94 % after 30 cycles.

Keywords: H2V3O8; Li-ion battery; electrochemistry; hydrothermal synthesis; synthesis design.