Electrochemical performances and gassing behavior of high surface area titanium niobium oxides

Abstract

A solvothermal synthesis is developed to build a 3D network of nanoparticles, enhancing the electrochemical performances of both TiNb₂O₇ and Ti₂Nb₁₀O₂₉, especially at high current densities, with up to 190 mA h g⁻¹ at 10C. A set of 11 mA h pouch cells combining the nanosized TiNb₂O₇ with LiMn_1.5Ni_0.5O₄ is tested and is the first to be reported for this material. Soft shell cells are used, not only to evaluate the electrochemical performances of this oxide in a larger scale battery, but also to assess its gassing behavior, a well-known limitation for application of Li₄Ti₅O₁₂ in hybrid electric vehicles. In order to evaluate the sole contribution of TiNb₂O₇ to the swelling, an additional set of soft shell TiNb₂O₇/Li(Ni_1/3Mn_1/3Co_1/3)O₂ cells is assembled and stored at 45 °C in a charged state. A higher swelling behavior is observed for TiNb₂O₇ in comparison to Li₄Ti₅O₁₂; a clear trend also appears between the surface area of the oxide and the amount of gassing. The swelling of TiNb₂O₇ or Ti₂Nb₁₀O₂₉ based pouch cells should be addressed before further industrial development of the two oxides can be considered.