摘要
Graphical What′s on tap today ? Li 4 Ti 5 O 12 (LTO) and 0.5 Li 2 MnO 3 ⋅0.5 LiNi 0.4 Co 0.2 Mn 0.4 O 2 (NCM) microspheres show a good electrochemical performance and high tap density. The Li 4 Ti 5 O 12 / x Li 2 MnO 3 ⋅(1- x ) LiMO 2 lithium-ion battery system can offer a higher energy density than Li 4 Ti 5 O 12 /LiCoO 2 cells. In this work, we propose an effective way to prepare nanosized Li 4 Ti 5 O 12 (LTO) microspheres and 0.5 Li 2 MnO 3 ⋅0.5 LiNi 0.4 Co 0.2 Mn 0.4 O 2 (NCM) microspheres by similar spray-drying methods. Both obtained materials are accumulated by primary nanoparticles and show a spherical morphology with particle distribution of 10–20 μm. The LTO microspheres deliver a tap density of 1.04 g cm −3 , while the tap density of NCM microspheres is 2.07 g cm −3 , which means an enhanced volumetric energy density. The as-prepared LTO microspheres have a reversible capacity of 170 mA h g −1 at 0.1 C and a capacity retention of 97 % after 250 cycles at 1 C. The NCM microspheres have an initial discharge capacity of 270 mA h g −1 with a corresponding Coulombic efficiency of 88 % at 0.03 C. Both materials show a relatively good rate capability. The Li 4 Ti 5 O 12 /0.5 Li 2 MnO 3 ⋅0.5 LiNi 0.4 Co 0.2 Mn 0.4 O 2 cells deliver a high cathode specific capacity of 273 mA h g −1 and good initial Coulombic efficiency of 88 % at 0.03 C, and can be developed for powering hybrid and plug-in hybrid vehicles.
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