Control of crystal size tailors the electrochemical performance of α-V2O5 as a Mg2+ intercalation host

Nanosizing α-V2O5 inhibits delamination during cycling in Mg electrolytes, reducing the voltage hysteresis and energy loss on the first cycle. This observation indicates that other factors, not just Mg diffusion, contribute to this energy loss.

Scientific Achievement

Reducing the particle size of α-V2O5 dramatically improved the energetics of Mg intercalation on the first cycle, whereas latter cycles showed no relative benefits, revealing that non-diffusive barriers contribute to current limitations in Mg batteries

Significance and Impact

This study reveals the impact of diffusive barriers on Mg-based energy storage, and indicates that exploration of non-diffusive limitations within Mg battery cycling are necessary to develop an energy dense Mg battery.

Research Details

  • Incorporation of a nanometric TiO2 seed reduced the size of α-V2O5 crystallites from 140 nm to 25 nm.
  • The 25 nm α-V2O5 crystallites displayed much lower voltage hysteresis (1.05 V) compared to 140 nm α-V2O5 (1.68 V) on the first cycle, but little difference was observed on latter cycles.
  • Structural, redox and elemental changes in α-V2O5 with Mg insertion and removal were confirmed by JCESR collaborators within the Materials Complexity Thrust.

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DOI: 10.1039/D1NR03080A

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