Mesoporous TiO2 Spheres as Advanced Anodes for Low-Cost, Safe, and High-Areal-Capacity Lithium-Ion Full Batteries

High cost, low safety, and low capacity are critical factors limiting the wide application of lithium (Li) batteries in our daily life. TiO2 and LiMn2O4 are both advanced electrode materials with advantages of low cost and high safety. Although TiO2/LiMn2O4 full batteries have been reported by several groups, these batteries only deliver low areal capacities (<1 mA cm(-2)), which is far from the criterion of commercially available Li-ion batteries (at least 2 mA cm(-2)). Here, we report high-areal-capacity TiO2/LiMn2O4 full batteries using a configuration containing anodes of mesoporous TiO2 spheres and cathodes of LiMn2O4 nanorods. Specifically, mesoporous TiO2 spheres are prepared by an improved solvothermal method, and their electrochemical performance is investigated using Li/TiO2 half-batteries. Because of their high specific areas, abundant pores, and stable structures, the mesoporous TiO2 spheres demonstrate remarkable cycling performances: after a test period as long as similar to 1000 h, they still deliver a capacity as high as 150 mAh g(-1) beyond 500 cycles at 1 C (1 C = 170 mAh g(-1)). LiMn2O4 nanorods are fabricated using beta-MnO2 nanorods as the precursor, and their electrochemical performances are studied using Li/LiMn2O4 half-batteries as well. Furthermore, we design TiO2-limited TiO2/LiMn2O4 full batteries and investigate their electrochemical performances. The mesoporous TiO2 sphere/LiMn2O4 nanorod full batteries exhibit areal capacities as high as similar to 4 mA cm(-2), which is much higher than the values of conventional TiO2/LiMn2O4 full batteries and comparable to those of commercially available Li-ion batteries. This work could make a substantial step toward the commercialization of TiO2/LiMn2O4-based full batteries.