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

A solvothermal synthesis is developed to build a 3D network of nanoparticles, enhancing the electrochemical performances of both TiNb 2 O 7 and Ti 2 Nb 10 O 29 , 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 TiNb 2 O 7 with LiMn 1.5 Ni 0.5 O 4 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 Li 4 Ti 5 O 12 in hybrid electric vehicles. In order to evaluate the sole contribution of TiNb 2 O 7 to the swelling, an additional set of soft shell TiNb 2 O 7 /Li(Ni 1/3 Mn 1/3 Co 1/3 )O 2 cells is assembled and stored at 45 °C in a charged state. A higher swelling behavior is observed for TiNb 2 O 7 in comparison to Li 4 Ti 5 O 12 ; a clear trend also appears between the surface area of the oxide and the amount of gassing. The swelling of TiNb 2 O 7 or Ti 2 Nb 10 O 29 based pouch cells should be addressed before further industrial development of the two oxides can be considered. High surface area TiNb 2 O 7 and Ti 2 Nb 10 O 29 show improved electrochemical performances, however full cell studies indicate a non-negligible gassing behavior.