Nanocomposites and nanomaterials

Nanosized bimetallic oxide CoTiO3 as anode material for lithium and sodium batteries
Shmatok Yu.V., Globa N.I., Lisnycha T.V., Kirillov S.A. 
Joint Department оf Electrochemical Energy Systems оf the NAS оf Ukraine. Vernadsky blvd, 38а, Kyiv, 03680, Ukraine. 
E-mail: yu.shmatok@gmail.com

Metal oxides are considered as possible candidates for use as anode materials for both lithium-ion and sodium-ion batteries. In view of this, a considerable attention is paid to various titanium oxides.
This work is focused on the synthesis, physico-chemical and electrochemical investigation of bimetallic oxide CoTiO3 with the perovskite structure. Initially, binary mixture of titanium and cobalt oxides was precipitated by LiOH from Co(NO3)2 and TiCl4 solution. Than previously washed and dried at 100 °C oxide mixture was annealed at 400-800 °C for 8 h. Obtained after annealing products were analyzed by the X-ray diffraction, scanning electron microscopy and porosimetry methods.
It was established by the X-ray diffraction analysis that the formation of crystalline oxides begins at a temperature of 500 °C and higher and the main product being CoTiO3 with a perovskite structure. There are also impurities of individual titanium and cobalt oxides, which amount decreases with increasing annealing temperature. As a result of an increase in the annealing temperature, a growth in the average particle size from ~ 50 nm to ~ 150 nm is observed, as well as a significant decrease in the specific surface area from over 200 m2/g to ~ 5 m2/g.
The specific characteristics of the obtained CoTiO3 samples in lithium and sodium cells were determined by galvanostatic cycling method. It is shown that the annealing temperature significantly affects the value of the specific capacity and its stability during cycling, both at low and high discharge current densities. The best specific characteristics were obtained after thermal annealing of the samples at the temperature of 700-800°C. In lithium cells CoTiO3 demonstrate stable cyclability with specific capacity of ~ 200 mAh/g at the current density of 100 mA/g and good rate capability at the discharge currents up to 5 A/g. In a case of sodium cells, the specific capacity is stable too, but much lower being ~ 100 mAh/g at the current density of 100 mA/g, and discharge currents reach 1 A/g.