Polydopamine Derived NaTi2(PO4)3-Carbon Core-Shell Nanostructures for Aqueous Batteries and Deionization Cells

Due to their stability and structural freedom, NASICON-structured materials such as NaTi₂(PO₄)₃ show a lot of promise as active electrode materials for aqueous batteries and deionization cells. However, due to their low intrinsic electronic conductivity, they must usually be composited with carbon to form suitable electrodes for power applications. In this work, two series of NaTi₂(PO₄)₃-carbon composite structures were successfully prepared by different approaches: postsynthetic pyrolytic treatment of citric acid and surface polymerized dopamine. The latter route allows for a superior carbon loading control and yields more uniform and continuous particle coatings. The homogeneity of the polydopamine derived core-shell carbon layer is supported by FTIR, TEM, and XPS analysis. Combustion elemental analysis also indicates significant nitrogen doping in the final carbonaceous structure. The galvanostatic charge and discharge cycling results show similar initial capacities and their retention, but at only half of the carbon loading in polydopamine derived samples. The overall results indicate that careful nanostructure engineering could yield materials with superior properties and stability suitable for various electrochemical applications such as aqueous Na-ion batteries and deionization cells.

Solvothermal Engineering of NaTi2(PO4)3 Nanomorphology for Applications in Aqueous Na-Ion Batteries

Aqueous Na-ion batteries are among the most discussed alternatives to the currently dominating Li-ion battery technology, in the area of stationary storage systems because of their sustainability, safety, stability, and environmental friendliness. The electrochemical properties such as ion insertion kinetics, practical capacity, cycling stability, or Coulombic efficiency are strongly dependent on the structure, morphology, and purity of an electrode material. The selection and optimization of materials synthesis route in many cases allows researchers to engineer materials with desired properties. In this work, we present a comprehensive study on size- and shape-controlled hydro(solvo)thermal synthesis of NaTi₂(PO₄)₃ nanoparticles. The effects of different alcohol/water synthesis media on nanoparticle phase purity, morphology, and size distribution are analyzed. Water activity in the synthesis media of different alcohol solutions is identified as the key parameter governing the nanoparticle phase purity, size, and shape. The careful engineering of NaTi₂(PO₄)₃ nanoparticle morphology allows control of the electrochemical performance and degradation of these materials as aqueous Na-ion battery electrodes.

Catalytic reduction of 4-nitrophenol using CuO@Na2Ti(PO4)2⋅H2O

This article presents the synthesis, property characterization and catalytic application of CuO-supported disodium titanium phosphate, (CuO@Na₂Ti(PO₄)₂⋅H₂O) for the reduction of industrial pollutant 4-nitrophenol (4-NP). A simple hydrothermal route was developed to synthesize CuO@Na₂Ti(PO₄)₂⋅H₂O catalyst (CuO@Na₂TiP) from beach sand ilmenite. The prepared CuO@Na₂TiP was characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and nitrogen adsorption-desorption isotherms. The catalyst 12 wt.% CuO@Na₂TiP showed the fastest reduction kinetics for 4-NP.