SnO₂ nanocrystals on self-organized TiO₂ nanotube array as three-dimensional electrode for lithium ion microbatteries

Three-dimensional (3D) anodes have been prepared for lithium ion microbatteries by depositing SnO₂ nanocrystals into self-organized TiO₂ nanotube arrays through the solvothermal method, with the SnO₂ crystal size less than 5 nm. The 3D SnO₂-TiO ₂ anodes exhibit excellent electrochemical performance with a good capacity retention of up to 70.8% over 100 cycles in the voltage range of 0.05-2.5 V. SnO₂ enhances the capacity to more than double that of bare TiO₂, while TiO₂ nanotubes accommodate the volume changes of SnO₂ during charge/discharge cycling. The amount of SnO₂ loading can be controlled by varying the reaction time. The capacity of the 3D electrodes is controlled by the TiO₂ tube length as well as by the amount of SnO₂ loading. The maximum reversible capacity of the present samples can reach as high as about 300 A h cm ^-2. © The Royal Society of Chemistry 2010.