High dispersion of TiO2 nanocrystals within porous carbon improves lithium storage capacity and can be applied batteries to LiNi0.5Mn1.5O4

Abstract

A new and simple strategy was developed to effectively disperse titanium dioxide (TiO2) nanocrystals into porous carbon (PC), and a series of hierarchical PC-TiO2 composites with different architectures were synthesized. By varying the amount of TiO2, from 30 wt% to 64 wt%, the lithium storage capacity of PC-TiO2 could be controllably varied from 546 mA h g(-1) to 446 mA h g(-1) under a current density of 50 mA g(-1). Also, very stable cycling performances and rate capabilities could be obtained at the rates of 50 mA g(-1) to 1600 mA g(-1). By further increasing the content of TiO2 to 93%, another new composite of TiO2-C was also prepared and it demonstrated a storage capacity of 352 mA h g(-1) at 50 mA g(-1), which is much higher than that for most reported TiO2 materials. Based on these results, new full cells with a LiNi0.5Mn1.5O4 cathode, such as PC-TiO2/LiNi0.5Mn1.5O4, were successfully assembled and investigated. This full cell not only delivered a high energy density of 413 W h kg(-1) but also showed a good rate capability and an energy retention of 90.5% over 100 cycles.