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.