Polymer‐Templated Mesoporous Li₄Ti₅O₁₂ as a High‐Rate and Long‐Life Anode Material for Rechargeable Li‐Ion Batteries

Abstract The synthesis, characterization and Li‐storage properties of cubic mesostructured lithium titanate spinel (Li₄Ti₅O₁₂) 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 m² 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 Li₄Ti₅O₁₂ obtained after heating to 600 °C at 10 °C min⁻¹ is virtually single phase, with minor traces of Li₂CO₃ 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 at 10C).