Cr III -doped vanadate glass: characterization and application as a cathode active material for lithium-ion batteries

Lithium iron phosphovanadate glasses containing Cr III were obtained by the melt-quench method and applied as cathode active materials in lithium-ion batteries. Amorphous glass structures were produced with compositions of 15Li 2 O·10Fe 2 O 3 ·5P 2 O 5 · x Cr 2 O 3 ·(70- x )V 2 O 5 and 15Li 2 O·(10- x )Fe 2 O 3 ·5P 2 O 5 · x Cr 2 O 3 ·70V 2 O 5 , where x varied from 0 to 5. Glass ceramic samples were prepared by annealing at 500 °C for 90 min. 57 Fe-Mössbauer spectra of 15Li 2 O‧10Fe 2 O 3 ‧5P 2 O 5 ‧70V 2 O 5 glass measured at room temperature before and after the annealing proved that some iron (III) atoms changed the structural role from distorted “octahedral” NWM sites to distorted “tetrahedral” NWF sites. High capacities of 250–300 mA‧h − 1 were achieved during discharge from 4.2 to 2.0 V. The substitution of V with Cr III was shown to have a considerable positive effect on the electrochemical performance of the glass material.