doping

Doped lithium titanate is known to be able to reversibly cycle in the potential range from 3 to 0.01 V and this ability depends both on the nature of the dopant and the doping level. In this work Li₄Ti₅O₁₂ samples doped with Nd in the amount of 0.5 to 2.0% were studied. It was shown that while being cycled in the extended potential range, the samples with the doping level from 0.5 to 1.0% demonstrated the highest capacity.

Nanotubes of bronze titanium dioxide (TiO₂(B)) doped with vanadium were synthesized through hydrothermal reaction. The obtained material possesses mesoporous structure and large specific surface area of 180 m²/g. It was found that the incorporation of vanadium into TiO₂(B) lattice increases the volume of a unit cell. Additionally, the conductivity rose up to three orders of magnitude for doped titanium dioxide reaching the value of 1.70 ⋅ 10^− 8 S/cm.

Within the work, an influence of manganese dopant on electrochemical performance of anatase titanium dioxide (Mn/Ti = 0.05; 0.1; 0.2) had been investigated. It was established that incorporation of Mn³⁺ into the TiO₂ lattice results in the formation of Ti_1 − xMn_xO₂ solid solution and increased anatase unit cell volume from 136.41 Å³ (undoped sample) to 137.25 Å³ (Mn/Ti = 0.05). The conductivity of doped TiO₂ rises up to two orders in magnitude.

A series of solid phases (mixed lithium-iron-manganese phosphates) of the common formula LiMn_yFe_1-yPO₄ (0 ≤ y ≤ 1) with a carbon coating on the particle surface was synthesized by mechanochemical activation with carbothermal reduction. The synthesized mixed phosphates were examined as promising cathode materials for lithium-ion batteries. The positive effect of replacement of a rather small fraction of iron by manganese is shown, which improves the electrochemical performance at the rates C/10–10C. The highest discharging capacity (above 160 mA·h/g at the C/10 rate, about 100 mA·h/g at the 10C rate) and cycling stability (the capacity decrease rate less than 0.05 mA·h/g per cycle at the 10 C rate) were established for the weakly doped cathode material LiMn_0.05Fe_0.95PO₄.