Synthesis and electrochemical performance of nano-sized Li4Ti5O12 with double surface modification of Ti(III) and carbon

Spinel Li4Ti5O12 nano-particles with double conductive surface modification of Ti(III) and carbon were synthesized by a facile solid-state reaction, in which the polyaniline (PANI) coated TiO2 particles and a lithium salt were used as precursors. On heat treatment under an argon atmosphere containing 5% H-2, the carbonization of PANI effectively restricted the particle-size growth of Li4Ti5O12 and reduced the surface Ti(IV) into Ti(III). The surface modification combined with tailored particle size can improve the surface conductivity and shorten the Li-ion diffusion path. Furthermore, both the Ti(III) surface modification and the tailored particles (50-70nm) have the potential to increase the solid solution (single-phase insertion/extraction) during the electrochemical process. Electrochemical analysis indicated that the presence of the solid solution is beneficial for Li-ion mobility. Thereby, the prepared Li4Ti5O12 displays high power performance.