Research progress on vanadium oxides for potassium-ion batteries

Potassium-ion batteries(PIBs)have been considered as promising candidates in the post-lithium-ion battery era.Till now,a large number of materials have been used as electrode materials for PIBs,among which vanadium oxides exhibit great potentiality.Vanadium oxides can provide multiple electron transfers during electrochemical reactions because vanadium possesses a variety of oxidation states.Meanwhile,their relatively low cost and superior material,structural,and physicochemical properties endow them with strong competitiveness.Although some inspiring research results have been achieved,many issues and challenges remain to be further addressed.Herein,we systematically summarize the research progress of vanadium oxides for PIBs.Then,feasible improvement strategies for the material properties and electrochemical performance are introduced.Finally,the existing challenges and perspectives are discussed with a view to promoting the development of vanadium oxides and accelerating their practical applications.

Preparation and Degradation Phenol Characterization of Ti/SnO_2-Sb-Mo Electrode Doped with Different Contents of Molybdenum

The Ti/SnO_2-Sb-Mo electrodes doped with different molar ratios of molybdenum(Mo) were prepared by sol—gel method in order to investigate the effect of Mo on the characterization of Ti/SnO_2-Sb—Mo electrodes.X-ray diffraction(XRD),field-emission scanning electron microscopy(FE-SEM),energy dispersive spectrometry(EDS),and linear scanning voltammetry(LSV) were used to scrutinize the coating material and the electrochemical activity.The concentration of phenol,the value of total organic carbon(TOC),the mineralization current efficiency(MCE) and the ultraviolet—visible spectroscopy(UV-Vis) spectrum of phenol solution were measured over the electrochemical degradation process of phenol to confirm the phenol degradation characterization of Ti/SnO_2-Sb-Mo electrodes.Results showed that the electrode at the Mo content of 1 at.%provided optimal catalytic activity for phenol degradation and the longest life time.The removal percentage of phenol and TOC were 99.62%and82.67%,respectively.The Ti/SnO_2-Sb-Mo electrode with 1 at.%of Mo reached maximum MCE of phenol oxidation.The kinetic investigation of phenol and TOC degradation displayed the pseudo-first order reaction model.The Ti/SnO_2-Sb-Mo electrode coating with 7 at.%Mo presented the highest oxygen evolution overpotential,indicating the diverse effects for different Mo molar ratio doping.