Li 4 Ti 5 O 12 Nanocrystals Synthesized by Carbon Templating from Solution Precursors Yield High Performance Thin Film Li‐Ion Battery Electrodes

Nanocrystals of Li 4 Ti 5 O 12 (LTO) have been prepared by processing an ethanol‐toluene solution of LiOEt and Ti(OiPr) 4 using a carbon black template. The mechanism of crystal growth has been tracked by SEM and TEM microscopies. The resulting nanocrystals grown using the carbon template (C‐LTO) show less aggregation than materials prepared from solution without the template (S‐LTO), which is reflected in higher surface area (27 m 2 /g) and concomitantly smaller particle size (58 nm) for C‐LTO compared to 20 m 2 /g and 201 nm for S‐LTO. Electrochemically, thin‐film electrodes composed of C‐LTO demonstrate reversible cycling, storing ∼160 mAh/g at both 1 C (175 mA/g) and 10 C current. Important is that resistance to charge transfer between the C‐LTO nanocrystals and added conducting carbon is 3 times smaller than that for S‐LTO. Accordingly, C‐LTO shows excellent rate capability, maintaining an energy‐storage capacity >150 mAh/g even at 100 C current. These characteristics solidify C‐LTO a suitable replacement for carbon as a Li‐ion battery anode.