HxMoO3−y nanobelts with sea water as electrolyte for high-performance pseudocapacitors and desalination devices

Pseudocapacitors, which store charge through fast reversible redox reactions occuring at the surface of the electrode, could offer higher specific capacitance than electrochemical double-layer capacitors (EDLCs). However, the prime pseudocapacitive phase, transition metal oxides usually have poor electronic conductivity, limiting their practical application. Here, we fabricated highly conductive HxMoO3−y nanobelts as electrode materials for pseudocapacitors. This electrode has demonstrated great electrochemical activity in various aqueous cation solutions with the highest volumetric capacitance of over 350 F cm−3. Significantly, this electrode has high specific capacitance as well as excellent cycling stability in sea water. Moreover, this hybrid composite also exhibits remarkable ion electrosorptive capacity (4 mg g−1) as a desalination electrode.