Three - Dimensionally Ordered Macroporous Amorphous C/TiO₂ Composite Electrodes for Lithium-ion Batteries

A facile method utilizing colloidal templating and sucrose as a carbon precursor is used to synthesize highly ordered, porous inverse opal structures as C/TiO₂ nanocomposites. Material characterization shows amorphous TiO₂ and a large pore size of ∼400 nm allowing for enhanced electrolyte penetration. C/TiO₂ inverse opals materials as electrodes in Li-ion battery half cells demonstrate discharge and charge capacities of ∼870 mAh g⁻¹ and 470 mAh g⁻¹, respectively, at a current density of 150 mA g⁻¹. The enhanced capacities, which surpass theoretical limits for TiO₂ and carbon based on intercalation reactions, are analyzed under voltammetric conditions to assess relative contributions to capacity from diffusion-limited intercalation and capacitive charge compensation reactions. The porous structure contributes to excellent capacity retention, rate performance and improved Coulombic efficiency (99.6% after 250 cycles), compared to individual carbon and TiO₂ inverse opals.