Structural water engaged disordered vanadium oxide nanosheets for high capacity aqueous potassium-ion storage.

ABSTRACT: Aqueous electrochemical energy storage devices using potassium-ions as charge carriers are attractive due to their superior safety, lower cost and excellent transport properties compared to other alkali ions. However, the accommodation of potassium-ions with satisfactory capacity and cyclability is difficult because the large ionic radius of potassium-ions causes structural distortion and instabilities even in layered electrodes. Here we report that water induces structural rearrangements of the vanadium-oxygen octahedra and enhances stability of the highly disordered potassium-intercalated vanadium oxide nanosheets. The vanadium oxide nanosheets engaged by structural water achieves high capacity (183?mAh?g-1 in half-cells at a scan rate of 5?mV?s-1, corresponding to 0.89 charge per vanadium) and excellent cyclability (62.5?mAh?g-1 in full cells after 5,000 cycles at 10 C). The promotional effects of structural water on the disordered vanadium oxide nanosheets will contribute to the exploration of disordered structures from earth-abundant elements for electrochemical energy storage.

SUBMITTER: Charles DS 

PROVIDER: S-EPMC5457508 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature