Effect of Electropolishing on Electrochemical Behaviours of Titanium Alloy Ti-10V-2Fe-3Al

The electrochemical behaviours of titanium alloy Ti-10V-2Fe-3Al after electropolishing in a self-developed electrolyte in comparison with conventional grinding were studied by electrochemical impedance spectroscopy （EIS）.Optical microscopy （OM）,scanning electron microscopy （SEM）,atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS） were used to evaluate the surface characteristics of the alloy.It was found from the EIS experiments that the polarization resistance （Rp） was increased,the double layer capacitance （Qc） was decreased and the electrochemical impedance of the alloy was enhanced by electropolishing.The electropolished surface was flat,smooth and bright and its roughness was 3.310 nm.To underline the advantage of electropolishing process against grinding to provide the anodic oxidation process with a higher quality substrate,the ground and electropolished titanium alloys were anodized in parallel under the same conditions.The corrosion behaviours of the two kinds of anodized titanium alloys were compared.It was revealed that electropolishing generated a high quality substrate and improved the corrosion resistance of anodic oxide film formed on titanium alloy Ti-10V-2Fe-3Al.Furthermore,the mechanism of electropolishing improving the corrosion resistance of the anodic oxide film was proposed.

Insights into the nitride-regulated processes at the electrolyte/electrode interface in quasi-solid-state lithium metal batteries

Gel polymer electrolytes(GPEs)are one of the promising candidates for high-energy-density quasi-solid-state lithium metal batteries(QSSLMBs),for their high ionic conductivity and excellent interfacial compatibility.The comprehension of dynamic evolution and structure-reactivity correlation at the GPE/Li interface becomes significant.Here,in situ electrochemical atomic force microscopy(EC-AFM)provides insights into the LiNO_(3)-regulated micromechanism of the Li plating/stripping processes upon cycles in GPE-based LMBs at nanoscale.The additive LiNO_(3)induces the formation of amorphous nitride SEI film and facilitates Li^(+) ion diffusion.It stabilizes a compatible interface and regulates the Li nucleation/growth at steady kinetics.The deposited Li is in the shape of chunks and tightly compact.The Li dissolution shows favorable reversibility,which guarantees the cycling performance of LMBs.In situ AFM monitoring provides a deep understanding into the dynamic evolution of Li deposition/dissolution and the interphasial properties of tunable SEI film,regulating the rational design of electrolyte and optimizing interfacial establishment for GPE-based QSSLMBs.