Temperature Dependence of the Electrical Properties of Na2Ti3O7/Na2Ti6O13/POMA Composites

Abstract

The temperature dependence of the electrical properties of composites formed by biphasic sodium titanate and poly(o-methoxyaniline) (Na2Ti3O7/Na2Ti6O13/POMA) with different concentrations of POMA (0%, 1%, 10%, 15%, 35% and 50%) in the ceramic matrix was determined from measurements of complex impedance. The structural details were studied by means of X-ray diffraction, confirming the formation of the Na2Ti3O7/Na2Ti6O13/POMA composites. The displacement of the (200) reflection from 2θ = 10.45° to 11.15° in the composites with 10 and 15% of POMA suggested the partial replacement of H+ for Na+ in the Na2Ti3O7 structure. The thermal properties were investigated by Thermogravimetry and Differential Thermal Analysis. The Thermogravimetry curves of the composites with POMA content of 1, 10 and 15% presented profiles similar to that of pure sodium titanate sample. The composites with 35 and 50% of POMA showed a process at temperatures around 60–70 °C, which was associated with water absorbed by the polymer. The analysis of the complex impedance spectroscopy measurements revealed that the electrical resistivity of the composites in the range from 0 to 35% increased by two orders of magnitude, with different values for each concentration. This positive temperature coefficient of resistivity was less noticeable in the composite with highest POMA mass content (50%). The rapid increase in resistivity caused an increase in the relaxation time calculated from the time domain. The electrical response of the 50% of POMA compound changes in relation to what was observed in the other compounds, which suggests that there is a saturation limit in the increase in resistivity with POMA content.

Effect of the Calcination Duration on the Electrochemical Properties of Na2Ti3O7 as Anode Material for Na-Ion Batteries

“…It should be noted that crystallographic structure and defects affect the electrochemical performance of NTO [23,24]. Moreover, both in the literature [25] and in our previous work [26], the higher capacities were obtained by NTO synthesized at 1000 • C than at 800 • C. If the temperature of the heat treatment affects electrochemical performance [25][26][27], it can be expected that the duration of the heat treatment could also impact the electrochemical properties.…”

The Li2Ti6O13 and Li2Zr6O13 composite as a high-performance anode for alkali-ion batteries: a molecular dynamics study

“…12 Differences on the electrical properties between the composite and individual components were reported. 12…”

“…[1][2][3][4][5]7 Various experimental strategies have been devoted to improve the performance of similarly active materials for anodes. [1][2][3][4][5][6][7][8][9][10][11][12] For instance, Li 2 TiO 3 was used as a co-material to stabilize the structure and enhance the electrode material with better electrochemical performance of the combined Li 4 Ti 5 O 12 -Li 2 TiO 3 whose ionic conductivity is higher than that of Li 4 Ti 5 O 12 . 8,9 Carbon-coating free, b-Li 2 TiO 3 delivers a specic capacity of 200 mA h g −1 within 100 cycles and 170 mA h g −1 aer 500 cycles preserving a coulombic efficiency above 97%.…”

“…11 In addition, the temperature dependence of electrical properties of composites formed by biphasic sodium titanate and poly(o-methoxyaniline) (Na 2 Ti 3 O 7 /Na 2 Ti 6 O 13 /POMA) with different concentrations of POMA was determined from complex impedance measurements. 12 Differences on the electrical properties between the composite and individual components were reported. 12 In this context we set out to search for a co-material which can be combined with Li 2 Ti 6 O 13 using molecular dynamics simulations.…”

“…12 Differences on the electrical properties between the composite and individual components were reported. 12 In this context we set out to search for a co-material which can be combined with Li 2 Ti 6 O 13 using molecular dynamics simulations. In fact, atomistic simulation is a powerful tool to investigate structure-property relations and for theoretical design of new materials.…”