Polymer‐Templated Mesoporous Li 4 Ti 5 O 12 as a High‐Rate and Long‐Life Anode Material for Rechargeable Li‐Ion Batteries

The synthesis, characterization and Li‐storage properties of cubic mesostructured lithium titanate spinel (Li 4 Ti 5 O 12 ) with uniform pores of diameter ≤15 nm and sub‐10 nm grains is reported. The material was prepared in powder form by sol–gel co‐assembly through a soft‐templating method using a poly(isobutylene)‐ block ‐poly(ethylene oxide) diblock copolymer structure‐directing agent. Electron microscopy demonstrates the mesoporous nature; the BET surface area is around 100 m 2  g −1 . Rietveld analysis of XRD data and results from XPS, FTIR and Raman spectroscopy indicate a large sensitivity of the phase composition to variations in the heating rate and temperature. Mesoporous Li 4 Ti 5 O 12 obtained after heating to 600 °C at 10 °C min −1 is virtually single phase, with minor traces of Li 2 CO 3 accumulated on the surface. Half‐cells with a Li metal anode display superior cycling (5 % capacity decay between the fifth and 300th cycles at C/2) and rate performance (>100 mA h g - 1LTOat 10C).