Polyoxometalates Modified Carbon Nanotubes for Electrochemical Capacitors

Surface modifications by pseudocapacitive polyoxometalates (POMs) on multi-walled carbon nanotubes (MWCNTs) have been investigated for electrochemical capacitors (ECs). The electrochemical behavior of two POM molecules, phosphomolybdate (PMo12) and silicomolybdate (SiMo12), have been studied. A Layer-by-Layer (LbL) deposition technique was utilized to coat thin layer PMo12 and SiMo12 on MWCNTs. This method was shown to be very effective and versatile in changing the surface chemistry of the MWCNT substrates. Several deposition sequences for POM layers have been demonstrated by combining the different POM chemistries to greatly enhance the pseudocapacitance on MWCNTs. This approach also enables to tailor design surface chemistries for many other applications.