Electrochemical deposition and pseudocapacitive behavior in urea-based quasi-ionic liquid electrolytes studied with X-ray absorption spectra

Co(II), Sn(II), V(III), Ni(II), Mn(II), and Ru(III) species in urea-based quasi-ILs were investigated using cyclic voltammograms and X-ray absorption near-edge structure (XANES) spectra. The excellent pseudocapacitive characteristics of MnO2-graphene nanocomposite electrodes in ILs, associated with the large variation of Mn oxidation state during charge and discharge cycles, were also elucidated using in situ XANES spectra.