Synthesis of Li2FeSiO4/C composite by sol-gel citric acid assisted method

Abstract

This paper describes a procedure for the synthesis of the composite Li2FeSiO4/C by sol-gel method using citric acid as a chelating agent; the resulting gel precursor was thermally treated in a slightly reductive atmosphere of nitrogen with five percent of hydrogen, whereupon the in situ decomposition of citric acid to carbon occurs during formation of the Li2FeSiO4. The obtained nanocrystalline powder (with mean crystallite size of 27nm) crystallized in the P21/n space group as confirmed by X-ray diffractometry. The morphology of the powder was examined by scanning electron microscopy which revealed a wide distribution of particles by size, from 100 to 500 nm. The material has been tested as cathode in lithium-ion cell and exhibits high efficiency and almost theoretical capacity.

Keywords

• lithium-ion batteries
• polianionic cathode materials
• Li2FeSiO4
• sol-gel method