Electrochemical properties of Ni4Nb2O9-based ceramics

Ga- and Ti-containing Ni4Nb2O9-based solid solutions for Ni-Selective electrodes

“…In particular, the conductivity of the Ni 3.95 Ga 0.0333 Nb 2 O 9 (x = 0.05) sample at a tempera ture of 500°C was determined to be 1 × 10 -4 S/cm, that is, half an order of magnitude higher than that of the undoped phase Ni 4 Nb 2 O 9 (3.16 × 10 -5 S/cm). More over, we observed a slight increase in total conductiv ity over the entire temperature range studied for the gallium and titanium doped niobates relative to their aluminum doped analogs [6]. On the whole, the tem perature dependences of conductivity for the new phases obtained here are similar in shape to those for the undoped compound Ni 4 Nb 2 O 9 [6,9].…”

“…The inert matrix used was polystyrene (PS) with an average molecular weight of 200000 or poly(vinyl chloride) with a molecular weight of 100000. The electrode con figuration was similar to that reported previously [6]. Before use, the electrodes were held in a 10 -3 M Ni(NO 3 ) 2 solution under short circuit conditions until the potential stabilized.…”

“…Their conductivity was measured as a function of temperature by a two probe method using an RCL meter (f = 1 kHz) in the temperature range 500-1300°C as described previously [6]. To gain further insight into electrical transport processes, we used impedance spectroscopy.…”

“…In addition to conventional applications of ceramic materials, a new area in the use of ceramics as elec trode active membrane materials for ion selective electrodes has recently been the subject of consider able attention [2][3][4][5][6][7]. The possibility of doping host compounds with heavy metal ions allows one to obtain modified materials capable of ↔ exchange, resulting in a potential jump across the interface [6,7].…”

“…The possibility of doping host compounds with heavy metal ions allows one to obtain modified materials capable of ↔ exchange, resulting in a potential jump across the interface [6,7].…”